金相試樣切割機(jī)的設(shè)計(jì)

金相試樣切割機(jī)的設(shè)計(jì),金相,試樣,切割機(jī),設(shè)計(jì) 河南科技學(xué)院 2009屆本科畢業(yè)設(shè)計(jì)（論文）,設(shè)計(jì)題目：金相試樣切割機(jī)的設(shè)計(jì) 學(xué)生姓名： 張靜 所在院系： 機(jī)電學(xué)院 所學(xué)專(zhuān)業(yè)： 機(jī)電技術(shù)教育 導(dǎo)師姓名： 劉貫軍,【摘 要】： 金相試樣切割機(jī)主要用于金相試樣的截取和各種材料的下料、切口等，在冶金、汽車(chē)、航空航天等制造業(yè)中應(yīng)用極為廣泛。20世紀(jì)90年代后，金相制樣技術(shù)發(fā)展極為迅速，金相試樣切割機(jī)作為金相取樣設(shè)備也取得了很大的進(jìn)步。 本設(shè)計(jì)通過(guò)對(duì)金相試樣切割機(jī)的整體造型、機(jī)械結(jié)構(gòu)和控制系統(tǒng)進(jìn)行了分析，完成了切割機(jī)主體結(jié)構(gòu)的設(shè)計(jì)，控制系統(tǒng)采用了銑床導(dǎo)軌原理，實(shí)現(xiàn)了低成本和手動(dòng)化。 最后確定切割機(jī)的裝配總圖。通過(guò)此次設(shè)計(jì)，掌握了相關(guān)設(shè)計(jì)的主要步驟，并對(duì)于Pro—E軟件應(yīng)用方面有了進(jìn)一步的提高。,1 引言 金屬零件的力學(xué)性能不僅與它的化學(xué)成分有關(guān)，也與它的金相組織密切有關(guān)。金相檢驗(yàn)是控制和評(píng)定產(chǎn)品質(zhì)量不可缺少的重要手段，是科學(xué)研究中研究新材料、新工藝和提高金屬制品內(nèi)在質(zhì)量的重要方法。 要進(jìn)行金相分析，就必須制備能用于微觀檢驗(yàn)的樣品— 金相試樣。通常，金相試樣的制備要經(jīng)過(guò)取樣、鑲嵌、磨光和拋光幾個(gè)步驟。每個(gè)步驟都應(yīng)該細(xì)心操作，因?yàn)槿魏坞A段上的失誤都可能影響最后的結(jié)果，因?yàn)檫@可能會(huì)造成組織假象，從而得出錯(cuò)誤的結(jié)論。金相試樣的制備是通過(guò)切割機(jī)、鑲嵌機(jī)、磨／拋光機(jī)來(lái)完成。金相試樣的截取是金相試樣制備過(guò)程中一個(gè)重要環(huán)節(jié)。截取試樣的方法有手鋸、鋸床、砂輪切割機(jī)和線切割機(jī)等等。根據(jù)零件的形狀和材料，選擇適當(dāng)?shù)姆椒▉?lái)切割。,目前砂輪切割機(jī)廣泛應(yīng)用于金相試樣的截取上，主要原因是其適應(yīng)性強(qiáng)，樹(shù)脂砂輪片可切割軟的金屬零件如銅、鋁及合金和硬的金屬零件如淬火后的碳鋼、高速鋼；金剛石切割機(jī)可切割超硬材料如硬質(zhì)合金、陶瓷等。另外其切割速度快、勞動(dòng)強(qiáng)度低、操作簡(jiǎn)便和切割成本低。選擇可靠性高的金相試樣切割機(jī)，可以提高制樣效率和質(zhì)量，降低成本，提高經(jīng)濟(jì)效益。,金相試樣切割機(jī)主要特點(diǎn)：本切割機(jī)的切割砂輪直接固定在與電動(dòng)機(jī)的軸同軸線相連接的軸上，利用滑板箱的橫向和縱向的移動(dòng)來(lái)切割固定在鉗口中的試樣 電動(dòng)機(jī)固定在底座上，軸套套在電動(dòng)機(jī)的軸上，砂輪片由螺母和夾片加以固定。固定在電動(dòng)機(jī)的前面的滑板箱上裝有可沿縱向移動(dòng)的加緊裝置，由手柄的轉(zhuǎn)動(dòng)來(lái)移動(dòng)鉗口把試樣夾緊在鉗座中，當(dāng)轉(zhuǎn)動(dòng)手柄時(shí)，就可以進(jìn)行試樣切割了。機(jī)器工作時(shí)，由罩殼將砂輪片等檔住，以防冷卻液飛濺和砂輪片碎裂時(shí)飛出傷人,2 設(shè)計(jì)要求 金相試樣切割機(jī)的具體設(shè)計(jì)要求為： （1）利用Pro--E軟件設(shè)計(jì) （2）確定結(jié)構(gòu)的尺寸 （3）繪制相應(yīng)的零件圖、實(shí)體圖及總裝配圖,3 切割機(jī)的總體設(shè)計(jì)過(guò)程 3.1 電動(dòng)機(jī)的選擇,,3.2 傳動(dòng)機(jī)構(gòu)的設(shè)計(jì) 3.2.1 軸的計(jì)算 3.2.2 軸的結(jié)構(gòu)設(shè)計(jì),,3.3 控制系統(tǒng)的設(shè)計(jì) 3.3.1夾具的主要結(jié)構(gòu)與使用,,3.3.2 進(jìn)給機(jī)構(gòu)的設(shè)計(jì),,,,上 滑 板,,,中 滑 板,,,下 滑 板,,,進(jìn) 給 裝 置,4 用Pro—E軟件對(duì)切割機(jī)進(jìn)行實(shí) 體造型和裝配 4.1 切割機(jī)各主要零件的實(shí)體造型,,軸 的 實(shí) 體 圖,,上 滑 板 的 實(shí) 體 圖,,中 滑 板 的 實(shí) 體 圖,,下 滑 板 的 實(shí)體 圖,,進(jìn) 給 系 統(tǒng) 的 實(shí)體 圖,4. 2 切割機(jī)的裝配,,切 割 機(jī) 的 內(nèi) 部 實(shí) 體 圖,5 結(jié)束語(yǔ) 在此次設(shè)計(jì)的過(guò)程中，培養(yǎng)了我的綜合運(yùn)用所學(xué)知識(shí)的能力，分析和解決實(shí)際中所遇到問(wèn)題的能力，并且能鞏固和深化我所學(xué)的專(zhuān)業(yè)知識(shí)，使我在調(diào)查研究和收集資料等方面有了顯著的提高，同時(shí)在理解分析能力、制定設(shè)計(jì)計(jì)算和繪圖能力方面有較大的進(jìn)步；另外我的技術(shù)分析和組織工作的能力也有一定程度的提高。,致謝 非常感謝學(xué)院領(lǐng)導(dǎo)和老師給我提供了這次良好的深入學(xué)習(xí)的機(jī)會(huì)和寬松的學(xué)習(xí)環(huán)境。通過(guò)這次畢業(yè)設(shè)計(jì)，不但使我將大學(xué)期間所學(xué)的專(zhuān)業(yè)知識(shí)再次回顧學(xué)習(xí)，而且也使我學(xué)到了專(zhuān)業(yè)領(lǐng)域中一些前沿的知識(shí)。非常感謝在本次設(shè)計(jì)中曾給予我耐心指導(dǎo)和親切關(guān)懷的老師及幫助過(guò)我的同學(xué)，正是由于他們的幫助和鼓勵(lì)才使我能夠在畢業(yè)設(shè)計(jì)過(guò)程中克服種種困難，最終順利完成論文，他們的學(xué)識(shí)和為人也深深地影響著我。在此，請(qǐng)?jiān)试S我再次向曾直接給予我多次指導(dǎo)的導(dǎo)師表示最忠誠(chéng)的敬意！同時(shí)也感謝百忙之中前來(lái)參加答辯的各位老師、專(zhuān)家和教授!,敬請(qǐng)指導(dǎo)批正!!!,謝謝!!! 答辯人：張靜,河南科技學(xué)院本科生畢業(yè)論文（設(shè)計(jì)）課題審核表 院（系）名稱(chēng) 機(jī)電學(xué)院 專(zhuān)業(yè)名稱(chēng) 機(jī)電技術(shù)教育042 指導(dǎo)教師姓名 劉貫軍 課題名稱(chēng) 金相試樣切割機(jī)設(shè)計(jì) 課題來(lái)源 自擬課題 立題理由 和所具備 的條件 　　 金相試樣切割機(jī)種類(lèi)很多，但適合本院專(zhuān)業(yè)實(shí)驗(yàn)室條件的用于制做透射電鏡樣品精密切割的切割機(jī)卻很少見(jiàn)，國(guó)外有符合要求的此類(lèi)產(chǎn)品，但價(jià)格昂貴。隨著科研工作的深入，設(shè)計(jì)制做一種高精度低成本的金相試樣切割機(jī)很有必要，而且設(shè)計(jì)條件已經(jīng)具備。 教研室 審批意見(jiàn) 教研室主任簽字： 年 月 日 畢業(yè)論文（設(shè) 計(jì)）工作領(lǐng)導(dǎo) 小組審批意見(jiàn) 組長(zhǎng)簽字：： 年 月 日 注：本表存院（系）備查。 學(xué)生姓名 張靜 班級(jí) 機(jī)教042 指導(dǎo)教師 劉貫軍 論文（設(shè)計(jì)）題目 金相試樣切割機(jī)的設(shè)計(jì) 目前已完成任務(wù) 1.制定畢業(yè)設(shè)計(jì)計(jì)劃 2.查找相關(guān)文獻(xiàn) 3.完成畢業(yè)論文開(kāi)題報(bào)告 是否符合任務(wù)書(shū)要求進(jìn)度：符合 尚需完成的任務(wù) 1.繼續(xù)對(duì)論文材料進(jìn)行組織和整理； 2.按照論文提綱，有步驟有計(jì)劃的開(kāi)展論文工作，存在問(wèn)題要及時(shí)與老師溝通； 3.對(duì)已完成的論文內(nèi)容進(jìn)行檢查審核，力求把問(wèn)題降到最少； 4.到規(guī)定的時(shí)間完成論文初稿； 5.根據(jù)指導(dǎo)老師的指導(dǎo)意見(jiàn)和全部材料完成論文； 能否按期完成論文（設(shè)計(jì)）：能 存在問(wèn)題和解決辦法 存 在 問(wèn) 題 閱讀資料不足，對(duì)論文主題的研究不夠透徹，且相關(guān)的理論知識(shí)還不夠全面； 與指導(dǎo)老師的交流不夠充分。 擬 采 取 的 辦 法 繼續(xù)查找資料，加強(qiáng)對(duì)相關(guān)理論知識(shí)的理解和掌握，應(yīng)多和老師交流，在老師的指導(dǎo)下更好完成設(shè)計(jì)。 指導(dǎo)教師簽 字 日期 年 月 日 教學(xué)院長(zhǎng)（系主任） 意 見(jiàn) 簽字： 年 月 日 河南科技學(xué)院本科畢業(yè)論文（設(shè)計(jì)）中期進(jìn)展情況檢查表 河南科技學(xué)院本科生畢業(yè)論文（設(shè)計(jì)）任務(wù)書(shū) 題目名稱(chēng) 金相試樣切割機(jī)的設(shè)計(jì) 學(xué)生姓名 張靜 所學(xué)專(zhuān)業(yè) 機(jī)教 學(xué)號(hào) 20040315049 指導(dǎo)教師姓名 劉貫軍 所學(xué)專(zhuān)業(yè) 機(jī)械設(shè)計(jì) 職稱(chēng) 教授 完成期限 2008 年 11 月 01 日 至 2009 年 05 月 24 日 一、論文（設(shè)計(jì)）主要內(nèi)容及主要技術(shù)指標(biāo) 1、連接金相試樣切割機(jī)的主要用途，國(guó)內(nèi)外研究及使用狀況（包括選擇國(guó)內(nèi)市場(chǎng)上此類(lèi)產(chǎn)品的性能及不足）； 2、研究制定設(shè)計(jì)方案； 3、對(duì)受力構(gòu)件進(jìn)行受力分析并有必要計(jì)算后方可進(jìn)行設(shè)計(jì)制圖； 二、 畢業(yè)論文（設(shè)計(jì)）的基本要求 1、 通過(guò)互聯(lián)網(wǎng)、校內(nèi)期刊數(shù)據(jù)庫(kù)等途徑了解切割機(jī)的工作原理、分析存在問(wèn)題，提出改進(jìn)方案； 2、 學(xué)習(xí)并熟練使用Pro—E繪圖軟件，并用其進(jìn)行零件和產(chǎn)品設(shè)計(jì)（重要部件應(yīng)有受力分析），提交任務(wù)內(nèi)的全部零件圖及部件總成圖。 3、 完成不少于2000字（單詞）的專(zhuān)業(yè)英文資料翻譯。 三、畢業(yè)論文（設(shè)計(jì)）進(jìn)度安排 2008年11月1日—12月30日 查找相關(guān)專(zhuān)業(yè)資料，熟悉Pro—E繪圖軟件的使用，提交開(kāi)題報(bào)告，論證設(shè)計(jì)方案、完成不少于2000單詞英文資料翻譯稿。 2009年2月16日—5月16日 基本完成畢業(yè)設(shè)計(jì)規(guī)定的繪圖任務(wù)。 2009年5月17日—5月24日 撰寫(xiě)畢業(yè)論文（設(shè)計(jì)說(shuō)明書(shū)）。 2009年5月24日交齊全部畢業(yè)設(shè)計(jì)資料。 畢業(yè)設(shè)計(jì)（論文）開(kāi)題報(bào)告 題目名稱(chēng)： 金相試樣切割機(jī) 學(xué)生姓名 張靜 專(zhuān)業(yè) 機(jī)電技術(shù)教育 班級(jí) 042 一、選題的目的意義 目前,正處在科學(xué)技術(shù)飛速發(fā)展的信息時(shí)代,自動(dòng)化、最優(yōu)化、集成化、智能化和精密化等使現(xiàn)代機(jī)械制造行業(yè)正經(jīng)歷著巨大的變化,也是其今后發(fā)展的必然趨勢(shì).金相取樣設(shè)備作為其中一個(gè)重要分支,正在由原來(lái)的手工操作逐漸走向半自動(dòng)化和自動(dòng)化.為此,我設(shè)計(jì)了對(duì)金相切割的半自動(dòng)化控制系統(tǒng). 與此同時(shí)在設(shè)計(jì)的過(guò)程中，能培養(yǎng)我綜合運(yùn)用所學(xué)知識(shí)，分析和解決實(shí)際中所遇到的問(wèn)題，并且能鞏固和深化我所學(xué)的專(zhuān)業(yè)知識(shí)，使我在調(diào)查研究和收集資料等方面有了顯著的提高，同時(shí)在理解分析能力、制定設(shè)計(jì)或試驗(yàn)方案能力、設(shè)計(jì)計(jì)算和繪圖能力方面有較大的進(jìn)步；另外我的技術(shù)分析和組織工作的能力也有一定程度的提高。 希望在此次畢業(yè)設(shè)計(jì)中，充分發(fā)揮出我們的創(chuàng)新能力，樹(shù)立良好的學(xué)術(shù)思想和工作作風(fēng)，牢牢把握住這次走上崗位之前的實(shí)踐機(jī)會(huì)，充分鍛煉出自己的工作能力。 二、國(guó)內(nèi)外研究綜述 金屬零件的力學(xué)性能不僅與它的化學(xué)成分有關(guān)，也與它的金相組織密切有關(guān)。金相檢驗(yàn)是控制和評(píng)定產(chǎn)品質(zhì)量不可缺少的重要手段，是科學(xué)研究中研究新材料、新工藝和提高金屬制品內(nèi)在質(zhì)量的重要方法。 要進(jìn)行金相分析，就必須制備能用于微觀檢驗(yàn)的樣品— — 金相試樣。通常，金相試樣的制備要經(jīng)過(guò)取樣、鑲嵌、磨光和拋光幾個(gè)步驟。每個(gè)步驟都應(yīng)該細(xì)心操作，因?yàn)槿魏坞A段上的失誤都可能影響最后的結(jié)果，因?yàn)檫@可能會(huì)造成組織假象，從而得出錯(cuò)誤的結(jié)論。金相試樣的制備是通過(guò)切割機(jī)、鑲嵌機(jī)、磨／拋光機(jī)來(lái)完成。金相試樣的截取是金相試樣制備過(guò)程中一個(gè)重要環(huán)節(jié)。截取試樣的方法有手鋸、鋸床、砂輪切割機(jī)和線切割機(jī)等等。根據(jù)零件的形狀和材料，選擇適當(dāng)?shù)姆椒▉?lái)切割。目前砂輪切割機(jī)廣泛應(yīng)用于金相試樣的截取上，主要原因是其適應(yīng)性強(qiáng)，樹(shù)脂砂輪片可切割軟的金屬零件如銅、鋁及合金和硬的金屬零件如淬火后的碳鋼、高速鋼；金剛石切割機(jī)可切割超硬材料如硬質(zhì)合金、陶瓷等。另外其切割速度快、勞動(dòng)強(qiáng)度低、操作簡(jiǎn)便和切割成本低。選擇可靠性高的金相試樣切割機(jī)，可以提高制樣效率和質(zhì)量，降低成本，提高經(jīng)濟(jì)效益。 金相試樣切割機(jī)主要特點(diǎn)：本切割機(jī)的切割砂輪直接固定在與電動(dòng)機(jī)的軸同軸線相連接的軸上，利用滑板箱的橫向和縱向的移動(dòng)來(lái)切割固定在鉗口中的試樣 電動(dòng)機(jī)固定在底座上，軸套套在電動(dòng)機(jī)的軸上，砂輪片由螺母和夾片加以固定。固定在電動(dòng)機(jī)的前面的滑板箱上裝有可沿縱向移動(dòng)的加緊裝置，由手柄的轉(zhuǎn)動(dòng)來(lái)移動(dòng)鉗口把試樣夾緊在鉗座中，當(dāng)轉(zhuǎn)動(dòng)手柄時(shí)，就可以進(jìn)行試樣切割了。機(jī)器工作時(shí)，由罩殼將砂輪片等檔住，以防冷卻液飛濺和砂輪片碎裂時(shí)飛出傷人。 三、畢業(yè)設(shè)計(jì)主要研究?jī)?nèi)容 1、研究切割機(jī)的切割原理； 2、利用Pre-E軟件繪制切割機(jī)模型； 3、繪制相應(yīng)的零件圖及總裝配圖 四、畢業(yè)設(shè)計(jì)（論文）的研究方法和技術(shù)路線 1．采用理論和實(shí)際操作相結(jié)合的方式再結(jié)合現(xiàn)代設(shè)計(jì)理念的基礎(chǔ)上，利用現(xiàn)有的條件來(lái)進(jìn)研究。 2．結(jié)合指導(dǎo)教師的教學(xué)經(jīng)驗(yàn)來(lái)重新完善和提高自己新的認(rèn)識(shí)和研究。 3．大量查閱有關(guān)書(shū)籍和資料來(lái)擴(kuò)充自己視野與認(rèn)識(shí)，提高理論成果的技術(shù)含量。 4．充分利用互連網(wǎng)來(lái)查找最新技術(shù)成果，提高自身的創(chuàng)新意識(shí)。 五、主要參考文獻(xiàn)與資料獲得情況 ［1］成大先。機(jī)械設(shè)計(jì)手冊(cè)[Ｍ]。北京：化學(xué)工業(yè)出版社，2004 ［2］成大先。機(jī)械設(shè)計(jì)手冊(cè) 第四版[Ｍ]。北京：化學(xué)工業(yè)出版社，2002 ［3］毛謙德,李振清。袖珍機(jī)械設(shè)計(jì)手冊(cè) 第三版[Ｍ]。北京：機(jī)械工業(yè)出版社，2007 ［4］機(jī)械設(shè)計(jì)實(shí)用手冊(cè)編委會(huì)。 機(jī)械設(shè)計(jì)實(shí)用手冊(cè)[Ｍ] 。北京：機(jī)械工業(yè)出版社，2008 ［5］陳立德。 機(jī)械設(shè)計(jì)基礎(chǔ)課程設(shè)計(jì)[Ｍ]。北京：高等教育出版社，2006 ［6］濮良貴，紀(jì)名剛。機(jī)械設(shè)計(jì) 第八版[Ｍ]。北京：高等教育出版社，2007 ［7］朱金波。Pro—E 3.0 工業(yè)產(chǎn)品設(shè)計(jì)完全掌握[Ｍ]。北京：兵器工業(yè)出版社，2007 ［8］金鑫，陳雪梅，賈長(zhǎng)治。Pro—E 3.0中文版機(jī)械設(shè)計(jì)專(zhuān)家指導(dǎo)教程[Ｍ]。 北京：機(jī)械工業(yè)出版社，2007 ［9］ 曹巖。Pro—E 3.0 機(jī)械設(shè)計(jì)實(shí)例精解[Ｍ]。北京：機(jī)械工業(yè)出版社，2007 ［10］朱文堅(jiān)，黃平，吳昌林。機(jī)械設(shè)計(jì)[Ｍ]。北京：機(jī)械工業(yè)出版社，2005 ［11］朱龍根。機(jī)械設(shè)計(jì)[Ｍ]。北京：機(jī)械工業(yè)出版社，2006 ［12］吳克堅(jiān)，于曉紅，錢(qián)瑞明。機(jī)械設(shè)計(jì)[Ｍ]。北京：高等教育出版社，2003 六、指導(dǎo)教師審批意見(jiàn) 年 月 日 使用NiSO4·6H2O過(guò)氧化氫為主要鹽對(duì)鎂合金進(jìn)行化學(xué)鍍鎳 李建中 ， 邵中材 ， 張新 ， 田衍文 學(xué)校的材料和冶金，東北大學(xué)，沈陽(yáng)110004 ，中國(guó) 大學(xué)環(huán)境與化學(xué)工程，沈陽(yáng)工業(yè)學(xué)院，沈陽(yáng)110168 ，中國(guó) 摘要 在本文件中，對(duì)鎂合金的化學(xué)鍍鎳進(jìn)行了研究，利用NiSO4·6H2O過(guò)氧化氫為主要鹽的化學(xué)鍍堿性的解決辦法。緩沖代理及電鍍參數(shù)對(duì)性能和結(jié)構(gòu)的鍍涂層的鎂合金的影響，用掃描電子顯微鏡（ SEM ） ，能量色散X射線能譜（ EDS ）和X -射線衍射（ XRD ）進(jìn)行了研究 。此外，使用電平衡對(duì)重量減輕/增益標(biāo)本沉浸進(jìn)行測(cè)試解決方案和鍍液測(cè)量，以評(píng)估侵蝕合金電鍍液。還對(duì)鍍涂層和基板之間的粘附性評(píng)價(jià)。通過(guò)正交試驗(yàn)對(duì)非氟的組成和友好環(huán)境鍍液進(jìn)行了優(yōu)化。 還發(fā)現(xiàn)在緩沖區(qū)劑（Na2CO3 ）加入鍍液有助于提高鍍層的成長(zhǎng)率，調(diào)整化學(xué)鍍涂層和基板之間的粘附性，并保持pH值范圍在8.5—11.5之間，這是成功取得利用NiSO4·6H2O 過(guò)氧化氫為主要鹽對(duì)鎂合金進(jìn)行化學(xué)鍍鎳的必要條件。二水檸檬酸鈉被認(rèn)為是鎂合金鍍液板塊中一個(gè)必不可少的組成部分，其最佳濃度30毫克 。所得鍍層的結(jié)晶的趨向（ 111 ） ，有優(yōu)點(diǎn)譬如低磷含量，高密度，低孔隙度，良好的耐蝕性和加強(qiáng)粘連。 1 簡(jiǎn)介 鎂合金應(yīng)用于各種場(chǎng)合，特別是在航空航天，汽車(chē)，機(jī)械和電子元件，近年來(lái)鎂合金的應(yīng)用顯穩(wěn)步增長(zhǎng)趨勢(shì)，主要展現(xiàn)出其具有吸引力的相結(jié)合的低密度，高強(qiáng)度重量比，良好的投能力，以及良好的力學(xué)和阻尼特性。然而，本質(zhì)上高鎂反應(yīng)及其合金通常有相對(duì)較差的耐蝕性，這是鎂合金應(yīng)用于實(shí)際環(huán)境的主要障礙之一【1—3】。 因此，采用表面工程技術(shù)是最合適的方法，以進(jìn)一步加耐蝕性。其中各種表面性能，如良好的抗腐蝕性和耐磨性，導(dǎo)電、導(dǎo)熱性和可焊性等存在統(tǒng)一性。至于鎂合金而言，主要的鹽化學(xué)鍍的解決辦法是重點(diǎn)關(guān)注基本碳酸鎳或鎳醋酸[ 4-9 ] ，這導(dǎo)致了高成本，低效率，不穩(wěn)定的化學(xué)鍍的應(yīng)用解決方案和小的應(yīng)用。此外，基本碳酸鎳或醋酸鎳電鍍解決方案還包括氟化物，是對(duì)環(huán)境有害，因此，迫切需要制定新的環(huán)保鍍液。由于具備高腐蝕性的鎂合金鍍液與NiSO4.6H2O或NiCl2.6H2O作為主要的鹽，這很難對(duì)鎂合金進(jìn)行化學(xué)鍍鎳。據(jù)報(bào)道[ 10 ]鎂及鎂合金在NaCl溶液中的腐蝕速率完全取決于緩沖氯化物的pH值。本研究的目的是找出緩沖劑，并確定如何解散緩沖劑影響鎂合金在NiSO4.6H2O堿性的解決方案，以及對(duì)非氟電鍍液的鎂合金NiSO4.6H2O作為主要鹽的微觀結(jié)構(gòu)，成分和腐蝕行為的現(xiàn)象進(jìn)行了詳細(xì)說(shuō)明。 2 試驗(yàn) 基板材料的研究使用了AZ91D鎂合金錠，鑄態(tài)合金。合金的化學(xué)組成見(jiàn)表1 。 Al Mn Ni Cu Zn Ca Si K Fe Mg 9.1 0.17 0.001 0.001 0.64 <0.01 <0.01 <0.01 <0.001 Bal 研究中所使用的基板，大小為50毫米* 40毫米* 20毫米?；迨前Ｄ镎撐闹刑岬綑C(jī)械拋光，多達(dá)1000道工序，以確保類(lèi)似的表面粗糙度。拋光的基板在徹底清洗之前，用蒸餾水預(yù)清洗的程序如表2所示。 超聲波脫脂丙酮 沉浸在60度10%氫氧化鈉溶液5分鐘 蒸餾水沖洗 在125毫克的鉻酸和110毫克的硝酸中酸洗45—60秒 蒸餾水沖洗 在250毫克70%的氟活化高頻解決10分鐘 蒸餾水沖洗 基板在氟激活后被風(fēng)干（最后一步前清洗程序） 。在一個(gè)典型的實(shí)驗(yàn)，測(cè)量最初被風(fēng)干的基板重量，然后迅速轉(zhuǎn)移到放置在一個(gè)水槽中具有80度恒定溫度的鍍液（ 1000毫升）的玻璃容器中。新鮮鍍液用于每一個(gè)實(shí)驗(yàn)，以避免任何改變濃度浴種浴組成和其他參數(shù)用于這些實(shí)驗(yàn)通過(guò)正交試驗(yàn)法在表3 。 優(yōu)化浴的組成和參數(shù) 浴種和參數(shù) 質(zhì)量 NiSO4.6H2O 25 g/L NaH2PO2.H2O 30 g/L C6H5Na3O7.2H2O 30 g/L Na2CO3 30 g/L NH3.H2O Adjusting pH PH value 11 Temperature 80+ -2度 最后確定權(quán)衡重量增加的標(biāo)本和涂層率以微米每小時(shí)計(jì)算。與此同時(shí)，為了研究每個(gè)緩沖區(qū)影響基板和找到一個(gè)適當(dāng)?shù)木彌_區(qū)鍍鎂合金，不用說(shuō)組成類(lèi)似于鍍液測(cè)試方案的次磷酸鈉，也準(zhǔn)備了模擬鎂合金鍍液腐蝕速率和行為的緩沖器。在每種情況下重復(fù)進(jìn)行涂層率報(bào)告的兩個(gè)實(shí)驗(yàn)。在美國(guó)，增長(zhǎng)率的鍍層測(cè)量使用電的比例，可達(dá)到0.1毫克的精度。在研究中， 鍍液的pH值由精度為pHS—25C模型PH值/毫伏表監(jiān)測(cè)。形態(tài)分析涂層用電子顯微鏡掃描。能量色散X射線譜分析用于確定其中磷的涂層。結(jié)晶涂層進(jìn)行了X射線數(shù)字/最高羅X射線衍射儀與銅的K -阿爾法輻射。鎂合金基板沉積的化學(xué)鍍層的結(jié)合強(qiáng)度可以通過(guò)測(cè)定劃痕檢測(cè)。 在從頭開(kāi)始試驗(yàn)中，試樣動(dòng)議以大約為11.4毫米/分鐘的恒定速度進(jìn)行。試樣劃痕的產(chǎn)生用球形尖端直徑為300微米金剛石壓頭。在腐蝕電位為3.5 wt 的氯化鈉溶液中進(jìn)行了裸基板和鍍鎳基板腐蝕行為的比較研究。 電化學(xué)電池用于腐蝕電位包括一個(gè)裸基板或鍍鎳基板為工作電極（暴露面積：1平方厘米） ，飽和甘汞電極（專(zhuān)家委員會(huì)）和鉑電極箔柜臺(tái)的測(cè)量。 河南科技學(xué)院 2009屆本科畢業(yè)設(shè)計(jì)（論文） 設(shè)計(jì)題目：金相試樣切割機(jī)的設(shè)計(jì) 學(xué)生姓名： 張靜 所在院系： 機(jī)電學(xué)院 所學(xué)專(zhuān)業(yè)： 機(jī)電技術(shù)教育 導(dǎo)師姓名： 劉貫軍 完成時(shí)間： 2009年 5 月24日 16 摘 要 金相試樣切割機(jī)主要用于金相試樣的截取和各種材料的下料、切口等，在冶金、汽車(chē)、航空航天等制造業(yè)中應(yīng)用極為廣泛。20世紀(jì)90年代后，金相制樣技術(shù)發(fā)展極為迅速，金相試樣切割機(jī)作為金相取樣設(shè)備也取得了很大的進(jìn)步。 本設(shè)計(jì)通過(guò)對(duì)金相試樣切割機(jī)的整體造型、機(jī)械結(jié)構(gòu)和控制系統(tǒng)進(jìn)行了分析，完成了切割機(jī)主體結(jié)構(gòu)的設(shè)計(jì)，控制系統(tǒng)采用了銑床導(dǎo)軌原理，實(shí)現(xiàn)了低成本和手動(dòng)化。 最后確定切割機(jī)的裝配總圖。通過(guò)此次設(shè)計(jì)，掌握了相關(guān)設(shè)計(jì)的主要步驟，并對(duì)于Pro—E軟件應(yīng)用方面有了進(jìn)一步的提高。 關(guān)鍵詞：金相試樣切割機(jī)，機(jī)械設(shè)計(jì)，手動(dòng)控制，控制系統(tǒng)，低成本 Metallographic sample cutting machine design Abstract Metallographic sample cutting machine mainly used for the interception of metallographic specimens and cutting material, incision, etc., in the metallurgical, automotive, aerospace and other manufacturing industries in a wide range of applications. After the 20th century, 90's, metallographic sample preparation is extremely rapid technological development, metallographic metallographic specimen cutting machine as the sampling equipment has also made great progress. The design of metallographic sample cutting machine's overall design, mechanical structure and control system analysis, completed the main structure of cutting machine design, control system uses the principle of the rail milling machine to achieve a low-cost-based and manual. Cutting machine to finalize the general layout of the assembly. With this design, is in control of the main steps related to the design and the Pro-E software applications has been further improved. Keywords： Metallographic sample cutting machines, Mechanical design, Manual control, Control systems, Low-cost 目 錄 1 引言 1 2 設(shè)計(jì)要求 1 3 切割機(jī)的總體設(shè)計(jì)過(guò)程 2 3.1 電動(dòng)機(jī)的選擇 2 3.1.1 選擇電動(dòng)機(jī)類(lèi)型和結(jié)構(gòu)形式 2 3.1.2 電動(dòng)機(jī)的參數(shù)選擇 2 3.2 傳動(dòng)機(jī)構(gòu)的設(shè)計(jì) 3 3.2.1 軸的計(jì)算 3 3.2.2 軸的結(jié)構(gòu)設(shè)計(jì) 4 3.3 控制系統(tǒng)的設(shè)計(jì) 4 3.3.1夾具的主要結(jié)構(gòu)與使用 4 3.3.2 進(jìn)給機(jī)構(gòu)的設(shè)計(jì) 5 4 用Pro/E軟件對(duì)切割機(jī)進(jìn)行實(shí)體造型和裝配 8 4.1 切割機(jī)各主要零件的實(shí)體造型 8 4.2 切割機(jī)的裝配 14 5 結(jié)束語(yǔ) 15 致謝 15 參考文獻(xiàn) 16 1 引言 金屬零件的力學(xué)性能不僅與它的化學(xué)成分有關(guān)，也與它的金相組織密切有關(guān)。金相檢驗(yàn)是控制和評(píng)定產(chǎn)品質(zhì)量不可缺少的重要手段，是科學(xué)研究中研究新材料、新工藝和提高金屬制品內(nèi)在質(zhì)量的重要方法。 要進(jìn)行金相分析，就必須制備能用于微觀檢驗(yàn)的樣品— — 金相試樣。通常，金相試樣的制備要經(jīng)過(guò)取樣、鑲嵌、磨光和拋光幾個(gè)步驟。每個(gè)步驟都應(yīng)該細(xì)心操作，因?yàn)槿魏坞A段上的失誤都可能影響最后的結(jié)果，因?yàn)檫@可能會(huì)造成組織假象，從而得出錯(cuò)誤的結(jié)論。金相試樣的制備是通過(guò)切割機(jī)、鑲嵌機(jī)、磨／拋光機(jī)來(lái)完成。金相試樣的截取是金相試樣制備過(guò)程中一個(gè)重要環(huán)節(jié)。截取試樣的方法有手鋸、鋸床、砂輪切割機(jī)和線切割機(jī)等等。根據(jù)零件的形狀和材料，選擇適當(dāng)?shù)姆椒▉?lái)切割。目前砂輪切割機(jī)廣泛應(yīng)用于金相試樣的截取上，主要原因是其適應(yīng)性強(qiáng)，樹(shù)脂砂輪片可切割軟的金屬零件如銅、鋁及合金和硬的金屬零件如淬火后的碳鋼、高速鋼；金剛石切割機(jī)可切割超硬材料如硬質(zhì)合金、陶瓷等。另外其切割速度快、勞動(dòng)強(qiáng)度低、操作簡(jiǎn)便和切割成本低。選擇可靠性高的金相試樣切割機(jī)，可以提高制樣效率和質(zhì)量，降低成本，提高經(jīng)濟(jì)效益。 金相試樣切割機(jī)主要特點(diǎn)：本切割機(jī)的切割砂輪直接固定在與電動(dòng)機(jī)的軸同軸線相連接的軸上，利用導(dǎo)軌的橫向和縱向的移動(dòng)來(lái)切割固定在鉗口中的試樣 電動(dòng)機(jī)固定在底座上，軸套套在電動(dòng)機(jī)的軸上，砂輪片由螺母和軸肩加以固定。加緊裝置固定在導(dǎo)軌上滑板，可沿縱向移動(dòng)的，由手柄的轉(zhuǎn)動(dòng)來(lái)移動(dòng)鉗口把試樣夾緊在鉗座中，當(dāng)轉(zhuǎn)動(dòng)手柄時(shí)，就可以進(jìn)行試樣切割了。機(jī)器工作時(shí)，由罩殼將砂輪片等檔住，以防冷卻液飛濺和砂輪片碎裂時(shí)飛出傷人。 2 設(shè)計(jì)要求 金相試樣切割機(jī)的具體設(shè)計(jì)要求為： （1）利用Pro/E軟件設(shè)計(jì) （2）確定結(jié)構(gòu)的尺寸 （3）繪制相應(yīng)的零件圖、實(shí)體圖及總裝配圖 3 切割機(jī)的總體設(shè)計(jì)過(guò)程 根據(jù)工件運(yùn)動(dòng)和砂輪片運(yùn)動(dòng)形式可將金相切割機(jī)分為兩類(lèi)，一類(lèi)為工件運(yùn)動(dòng)，砂輪片固定不動(dòng)的切割機(jī)；另一類(lèi)為工件固定不動(dòng)，砂輪片運(yùn)動(dòng)的切割機(jī)。本切割機(jī)采用的運(yùn)動(dòng)方式是工件運(yùn)動(dòng)，砂輪片固定不動(dòng)的切割模式。 3.1 電動(dòng)機(jī)的選擇 3.1.1 選擇電動(dòng)機(jī)類(lèi)型和結(jié)構(gòu)形式 根據(jù)已知的電源、工作條件、和功率特點(diǎn)選擇電動(dòng)機(jī)的類(lèi)型和結(jié)構(gòu)形式是：Y2系列三相異步電動(dòng)機(jī)。 3.1.2 電動(dòng)機(jī)的參數(shù)選擇 根據(jù)設(shè)計(jì)任務(wù)書(shū)，由有關(guān)手冊(cè)查出電動(dòng)機(jī)性能參數(shù)如下： 表1 電動(dòng)機(jī)性能參數(shù) 電動(dòng)機(jī)型號(hào) 額定功率 滿載轉(zhuǎn)速 kw r/min Y2-631-4 0.12 1370 電動(dòng)機(jī)主要外形如圖1所示，安裝尺寸列于下表2： 圖1 電動(dòng)機(jī)主要外形和安裝尺寸 表2 電動(dòng)機(jī)的安裝尺寸 中心高H 外形尺寸 L×AC×HD 底腳安裝尺寸 A×B 底腳螺栓孔直徑 K 軸伸尺寸 D×E 裝鍵部位尺寸 F×G 160 225×130×180 100×80 7 11×23 4×8.5 3.2 傳動(dòng)機(jī)構(gòu)的設(shè)計(jì) 切割機(jī)的切割砂輪直接固定在與電動(dòng)機(jī)的軸同軸線相連接的軸上，根據(jù)切割砂輪的規(guī)格尺寸設(shè)計(jì)軸的尺寸并檢驗(yàn)。 3.2.1 軸的計(jì)算 1) 安裝切割砂輪的軸與電動(dòng)機(jī)軸直接通過(guò)套筒連接，首先都軸進(jìn)行設(shè)計(jì)計(jì)算。已知軸上的功率P，轉(zhuǎn)速n，求轉(zhuǎn)矩T： P=0.12KW n=1370r/min T=9550P/n =0.84N.M 2) 初步確定軸的最小直徑 選取軸的材料為45鋼，調(diào)質(zhì)處理。根據(jù)有關(guān)手冊(cè)取，于是得 dmin=A0=112 =4.97 mm 輸入軸的最小直徑顯然是安裝切割機(jī)砂輪處軸的直徑dⅠ-Ⅱ,。根據(jù)砂輪的規(guī)格尺寸，故dⅠ-Ⅱ = 10 mm，LⅠ-Ⅱ = 8 mm 。 3）軸的撓度計(jì)算 由于軸與電機(jī)軸同步轉(zhuǎn)動(dòng)，選擇聯(lián)軸器。為了方便，聯(lián)軸器與軸做成一體，長(zhǎng)度L = 40 mm ，其中LⅠ-Ⅱ = 8 mm ，則LⅡ-Ⅲ = 32 mm 。 撓度計(jì)算公式如下： ymax=Pa2(3L-a)/6EI<=[y] 式中： P—切割時(shí)作用在軸上的力，P=4.9N（這一力很小）； a—切割點(diǎn)至支撐點(diǎn)的距離，即LⅡ-Ⅲ，a=32mm； L—軸的長(zhǎng)度，L=40mm； E—彈性模量，查手冊(cè)：E=206GPa； I—慣矩，I=∏d4 /64; [y]—許用撓度，[y]=0.05mm。 則 d>=19.5mm 為了滿足切割砂輪的軸向定位要求，Ⅰ-Ⅱ軸段右端需制出一軸肩，而且為了避免電動(dòng)機(jī)的軸向竄動(dòng)，選擇推力球軸承加以軸向固定。根據(jù)標(biāo)準(zhǔn)件軸承的內(nèi)徑尺寸，故?、?Ⅲ段的直徑dⅡ-Ⅲ=20mm.軸承類(lèi)型：51204（GB/T 301--1995） 。 砂輪的軸向固定輪安裝在軸上后，左端用軸肩來(lái)固定，右端使用螺母。所以軸的Ⅰ-Ⅱ段攻有螺紋，由于要留有砂輪裝配空間，故螺紋長(zhǎng)度占有6mm。螺母規(guī)格：D=M10（GB/T 6174） 3.2.2 軸的結(jié)構(gòu)設(shè)計(jì) 圖2 軸 3.3 控制系統(tǒng)的設(shè)計(jì) 3.3.1夾具的主要結(jié)構(gòu)與使用 如圖所示,該夾具由手輪、絲桿、絲母、左夾具、右?jiàn)A具組成。絲母 和左夾具是固定不動(dòng)的,當(dāng)旋轉(zhuǎn)手輪時(shí),絲桿依靠螺旋作用前進(jìn)或后退,用來(lái)夾緊或松開(kāi)工件，絲母在夾緊或松開(kāi)過(guò)程中起導(dǎo)向和支承作用。由此可見(jiàn)這種夾具是依靠非常簡(jiǎn)單的螺旋運(yùn)動(dòng)前進(jìn)或后退,來(lái)實(shí)現(xiàn)對(duì)工件的夾緊或松開(kāi)。例如我們驅(qū)動(dòng)夾具壓桿前進(jìn)50mm ,壓桿的螺距為5mm ,當(dāng)手輪旋轉(zhuǎn)一周時(shí)壓桿前進(jìn)了5mm。通過(guò)計(jì)算可知,若要實(shí)現(xiàn)壓桿前進(jìn)50mm ,手輪需旋轉(zhuǎn)10圈。 圖3 夾緊裝置 關(guān)于夾緊力的計(jì)算,夾緊力的計(jì)算可有下式進(jìn)行: W = QL/（r1tgΦ1 + r2tg(α+φ2)） 式中: Q —手驅(qū)動(dòng)力　取Q = 300N; L —手輪半徑　L = 10mm; r1 —壓桿端部與工件間的當(dāng)量摩擦半徑, 假設(shè)壓桿與工件為點(diǎn)接觸,則r1 = 0; r2 —壓桿螺紋中徑的一半, r2 = 4.5mm(注:壓桿螺紋為10mm) ; Φ1 —壓桿端部與工件間的摩擦角, tgΦ1 = 01; α—壓桿螺紋升角;α= 2°28′; Φ2 —壓桿螺紋螺旋副的當(dāng)量摩擦角，Φ2 = 6°38 則夾緊力W≈1974(N) 。 對(duì)工件的夾緊力為: W′= Wf = 9868 ×0.7 =1382(N) f —卡爪與壓桿之間的摩擦系數(shù) 由此得出,該夾具已完全可以實(shí)現(xiàn)對(duì)工件的夾緊(一般砂輪切割機(jī)夾具的的夾緊力只需800N～1300N) 。 3.3.2 進(jìn)給機(jī)構(gòu)的設(shè)計(jì) 導(dǎo)軌由橫向螺桿和縱向螺桿帶動(dòng)，橫向螺桿通過(guò)導(dǎo)塊運(yùn)動(dòng)帶動(dòng)導(dǎo)軌橫向移動(dòng)，縱向螺桿通過(guò)導(dǎo)塊運(yùn)動(dòng)帶動(dòng)導(dǎo)軌縱向移動(dòng)。螺桿一端分別安裝有手輪，手輪上刻有刻度，以滿足不同的切割要求。 導(dǎo)軌為了實(shí)現(xiàn)橫向和縱向進(jìn)給，可以把工作臺(tái)分為上滑板、中滑板、下滑板三部分。導(dǎo)軌的行程為80mm，則滑板尺寸的長(zhǎng)、寬為100mm，而高度隨情況而定，具體數(shù)值見(jiàn)圖4、圖5、圖6。 由于橫向及縱向螺桿在進(jìn)給過(guò)程中受力很小，強(qiáng)度及其他性能指標(biāo)均能滿足。根據(jù)情況選擇螺桿直徑為12mm，螺距為5mm，當(dāng)手輪旋轉(zhuǎn)一周時(shí)螺桿前進(jìn)了5mm。。手輪直徑比螺桿稍大為20mm，上面刻有100個(gè)小格，每小格為0.05mm。導(dǎo)塊與螺桿裝配一起，在螺桿旋轉(zhuǎn)時(shí)導(dǎo)塊分別引領(lǐng)和帶動(dòng)上滑板或中滑板進(jìn)行橫向或縱向移動(dòng)。故導(dǎo)塊上開(kāi)有螺紋孔，為了與螺桿配合，孔徑為12mm，螺距為5mm。具體位置尺寸見(jiàn)圖4、圖5。 為保證導(dǎo)軌正常工作，導(dǎo)軌滑動(dòng)表面之間應(yīng)保持適當(dāng)?shù)拈g隙。間隙過(guò)小，會(huì)增加摩擦阻力；間隙過(guò)大，會(huì)降低導(dǎo)向精度。導(dǎo)軌的間隙如依靠刮研來(lái)保證，工作量很大，而且導(dǎo)軌經(jīng)過(guò)長(zhǎng)期使用后，會(huì)因磨損而增大間隙，需要及時(shí)調(diào)整，故導(dǎo)軌應(yīng)有間隙調(diào)整裝置。本切割機(jī)采用燕尾槽型導(dǎo)軌，需要在水平方向上調(diào)整間隙。用螺釘調(diào)整鑲條位置。 具體如下： 圖4 上滑板 圖5 中滑板 圖6 下滑板 圖7 進(jìn)給裝置 4 用Pro/E軟件對(duì)切割機(jī)進(jìn)行實(shí)體造型和裝配 4.1 切割機(jī)各主要零件的實(shí)體造型 圖8 軸的實(shí)體圖 圖9 左夾具實(shí)體圖 圖10 右?jiàn)A具實(shí)體圖 圖11 絲桿實(shí)體圖 圖12 夾具實(shí)體圖 圖13 上滑板實(shí)體圖 圖14 中滑板實(shí)體圖 圖15 下滑板實(shí)體圖 圖16 進(jìn)給系統(tǒng)實(shí)體圖 4.2 切割機(jī)的裝配 5 結(jié)束語(yǔ) 在此次設(shè)計(jì)的過(guò)程中，培養(yǎng)了我的綜合運(yùn)用所學(xué)知識(shí)的能力，分析和解決實(shí)際中所遇到問(wèn)題的能力，并且能鞏固和深化我所學(xué)的專(zhuān)業(yè)知識(shí)，使我在調(diào)查研究和收集資料等方面有了顯著的提高，同時(shí)在理解分析能力、制定設(shè)計(jì)計(jì)算和繪圖能力方面有較大的進(jìn)步；另外我的技術(shù)分析和組織工作的能力也有一定程度的提高。 致謝 非常感謝學(xué)院領(lǐng)導(dǎo)和老師給我提供了這次良好的深入學(xué)習(xí)的機(jī)會(huì)和寬松的學(xué)習(xí)環(huán)境。通過(guò)這次畢業(yè)設(shè)計(jì)，不但使我將大學(xué)期間所學(xué)的專(zhuān)業(yè)知識(shí)再次回顧學(xué)習(xí)，而且也使我學(xué)到了專(zhuān)業(yè)領(lǐng)域中一些前沿的知識(shí)。非常感謝在本次設(shè)計(jì)中曾給予我耐心指導(dǎo)和親切關(guān)懷的老師及幫助過(guò)我的同學(xué)，正是由于他們的幫助和鼓勵(lì)才使我能夠在畢業(yè)設(shè)計(jì)過(guò)程中克服種種困難，最終順利完成論文，他們的學(xué)識(shí)和為人也深深地影響著我。在此，請(qǐng)?jiān)试S我再次向曾直接給予我多次指導(dǎo)的導(dǎo)師表示最忠誠(chéng)的敬意！同時(shí)也感謝百忙之中前來(lái)參加答辯的各位老師、專(zhuān)家和教授! 參考文獻(xiàn) ［1］成大先.機(jī)械設(shè)計(jì)手冊(cè)[Ｍ].北京：化學(xué)工業(yè)出版社，2004 ［2］成大先.機(jī)械設(shè)計(jì)手冊(cè) 第四版[Ｍ].北京：化學(xué)工業(yè)出版社，2002 ［3］毛謙德,李振清.袖珍機(jī)械設(shè)計(jì)手冊(cè) 第三版[Ｍ].北京：機(jī)械工業(yè)出版社，2007 ［4］機(jī)械設(shè)計(jì)實(shí)用手冊(cè)編委會(huì). 機(jī)械設(shè)計(jì)實(shí)用手冊(cè)[Ｍ].北京：機(jī)械工業(yè)出版社，2008 ［5］陳立德. 機(jī)械設(shè)計(jì)基礎(chǔ)課程設(shè)計(jì)[Ｍ].北京：高等教育出版社，2006 ［6］濮良貴，紀(jì)名剛.機(jī)械設(shè)計(jì) 第八版[Ｍ].北京：高等教育出版社，2007 ［7］朱金波.Pro/E 3.0 工業(yè)產(chǎn)品設(shè)計(jì)完全掌握[Ｍ].北京：兵器工業(yè)出版社，2007 ［8］金鑫，陳雪梅，賈長(zhǎng)治.Pro/E 3.0中文版機(jī)械設(shè)計(jì)專(zhuān)家指導(dǎo)教程[Ｍ]. 北京：機(jī)械工業(yè)出版社，2007 ［9］ 曹巖.Pro/E 3.0 機(jī)械設(shè)計(jì)實(shí)例精解[Ｍ].北京：機(jī)械工業(yè)出版社，2007 ［10］朱文堅(jiān)，黃平，吳昌林.機(jī)械設(shè)計(jì)[Ｍ].北京：機(jī)械工業(yè)出版社，2005 ［11］朱龍根.機(jī)械設(shè)計(jì)[Ｍ].北京：機(jī)械工業(yè)出版社，2006 ［12］吳克堅(jiān)，于曉紅，錢(qián)瑞明.機(jī)械設(shè)計(jì)[Ｍ].北京：高等教育出版社，2003 The electroless nickel-plating on magnesium alloy using NiSO4d6H2O as the main salt Jianzhong Lia,*, Zhongcai Shaob, Xin Zhanga, Yanwen Tiana aSchool of materials and metallurgy, Northeastern University, Shenyang 110004, China bFaculty of Environment and Chemical Engineering, Shenyang Institute of Technology, Shenyang 110168, China Received 23 July 2004; accepted in revised form 19 December 2004 Available online 26 January 2005 Abstract In this paper, the electroless nickel-plating on magnesium alloy was studied, using NiSO4d 6H2O as the main salt in the electroless plating alkaline solutions. The effects of the buffer agent and plating parameters on the properties and structures of the plating coatings on magnesium alloy were investigated by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Xray diffraction (XRD). In addition, the weight loss/gain of the specimens immersed in the test solution and plating bath was measured by using the electro-balance, to evaluate the erosion of the alloy in the plating solutions. The adhesion between the electroless plating coatings and the substrates was also evaluated. The compositions of the non-fluoride and environmentally friendly plating bath were optimized through Latin orthogonal experiment. The buffer agent (Na2CO3) added to the plating bath was found to be useful in increasing the growth rate of the plating coating, adjusting the adhesion between the electroless plating coatings and the substrates, and maintaining the pH value within the range of 8.5–11.5, which is required for the successful electroless nickel-plating on magnesium alloy with NiSO4d 6H2O as the main salt. Trisodium citrate dihydrate was found to be an essential component of the plating bath to plate magnesium alloy, with an optimum concentration of 30 g L_1. The obtained plating coatings are crystalline with preferential orientation of (111), having advantages such as lowphosphorus content, high density, low-porosity, good corrosion resistance and strengthened adhesion. D 2004 Elsevier B.V. All rights reserved. Keywords: Magnesium alloy; Electroless plating; Buffer; Corrosion resistance; Adhesion 1. Introduction The use of magnesium alloys in a variety of applications, particularly in aerospace, automobiles, and mechanical and electronic components, has increased steadily in recent years as magnesium alloys exhibit an attractive combination of low density, high strength-to-weight ratio, excellent castability, and good mechanical and damping characteristics. However, magnesium is intrinsically highly reactive and its alloys usually have relatively poor corrosion resistance, which is actually one of the main obstacles to the application of magnesium alloys in practical environments [1–3]. Hence, the application of a surface engineering technique is the most appropriate method to further enhance the corrosion resistance. Among the various surface engineering techniques that are available for this purpose, coating by electroless nickel is of special interest especially in the electronic industry, due to the possession of a combination of properties, such as good corrosion and wear resistance, deposit uniformity, electrical and thermal conductivity, and solderability etc. As far as magnesium alloys are concerned, the main salts of electroless plating solutions mostly focus attentions on basic nickel carbonate or nickel acetate [4–9], which result in high-cost, low-efficiency, instability of electroless plating solutions and little applications. In addition, the basic nickel carbonate or nickel acetate of plating solutions yet including fluoride, are harmful to the environment, therefore, it is urgently needed to develop new environmentally friendly plating bath. It is difficult to carry 0257-8972/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.surfcoat.2004.12.009 * Corresponding author. Tel.: +86 24 8368 7731; fax: +86 24 2398 1731. E-mail address: mengsuo66@163.com (J. Li). Surface & Coatings Technology 200 (2006) 3010– 3015 www.elsevier.com/locate/surfcoat out electroless plating on magnesium alloys due to the highcorrosion rate of magnesium alloys in the plating bath with NiSO4d 6H2O or NiCl2d 6H2O as the main salt. It is reported [10] that the corrosion rate of magnesium and its alloys in NaCl solutions solely depends on the pH of the buffered chloride solutions. The objective of this study was to find a buffer agent and determine how the buffer agent affects the dissolution of magnesium alloy in NiSO4d 6H2O alkaline solutions, and the non-fluoride plating solutions for magnesium alloy with NiSO4d 6H2O as the main salt. The microstructure, compositions and corrosion behavior of the coatings were investigated in detail. 2. Experimental The substrate material used in the research was AZ91D ingot-cast alloy. The chemical composition of the alloy is given in Table 1. Substrates with a size of 50 mm_40 mm_20 mm were used in the research. The substrates were mechanically polished with emery papers up to 1000 grit to ensure similar surface roughness. The polished substrates were thoroughly washed with distilled water before passing through the precleaning procedure as shown in Table 2. The substrates were air-dried after the fluoride activation (the last step in the pre-cleaning procedure). In a typical experiment, the initial weight of a air-dried substrate was measured and then quickly transferred to the plating bath (1000 mL) in a glass container placed in a water bath with a constant temperature of 80 8C. A fresh bath was used for each experiment to avoid any change in concentration of bath species. The bath compositions and other parameters used in these experiments are given through Latin orthogonal experiment in Table 3. Final weights of the specimens were determined and the coating rates in micrometer per hour were calculated from the weight gain. At the same time, in order to study the each buffer’s influence on the substrates and find a buffer appropriate for the electroless plating on magnesium alloy, test solutions with compositions similar to those of the plating bath except that sodium hypophosphite was not added, were prepared to simulate the corrosion rates of magnesium alloy in plating bath and the behaviors of the buffers. Duplicate experiments were conducted in each case, and the coating rate reported is the average of two experiments. The growth rates of the plating coating were measured using the electro-balance made in America, which is the 0.1 mg precision. In the research, the pH value of plating bath was monitored by a pHS-25C model of precision pH/mV meter. Morphology of the coatings was analyzed using a scanning electron microscope. The energy dispersive X-ray spectroscopy analysis was used for determining the content of phosphorus in the coatings. Crystallinity of the coatings was investigated by Rigaku D/ max-rA X-ray diffractometer with Cu K-alpha radiation. The adhesion strength of the electrolessly deposited nickel coatings to the magnesium alloy substrates was determined by scratch test. During the scratch test, the specimen was moved at a constant speed of approximately 11.4 mm/min. Scratches were generated on the specimen using a diamond indenter with a spherical tip of 300 Am in diameter. Corrosion potential measurement in 3.5 wt.% NaCl solution was carried out to comparatively investigate the corrosion behaviors of the bare substrate and the nickel-plated substrates. The electrochemical cell used for corrosion potential measurement consisted of a bare substrate or a nickel-plated substrate as the working electrode (exposed area: 1 cm2), a saturated calomel electrode (SCE), and a platinum-foil counter electrode. Table 1 Chemical composition of the AZ91D alloy (in wt.%) Al Mn Ni Cu Zn Ca Si K Fe Mg 9.1 0.17 0.001 0.001 0.64 b0.01 b0.01 b0.01 b0.001 Bal Table 2 Optimized pre-cleaning procedure Table 3 Optimized bath composition and parameters Bath species and parameters Quantity NiSO4d 6H2O 25 g/L NaH2PO2d H2O 30 g/L C6H5Na3O7d 2H2O 30 g/L Na2CO3 30 g/L NH3d H2O Adjusting pH pH value 11 Temperature 80F2 8C J. Li et al. / Surface & Coatings Technology 200 (2006) 3010–3015 3011 3. Results and discussion 3.1. The buffers’ behaviors in the test NiSO4 solutions and the choice of an appropriate buffer Fig. 1 shows the variation of weight loss of magnesium alloy as a function of the immersion time with different buffers in the test solutions. The compositions and the controlled temperature of the test solutions were similar to those of the plating bath except that sodium hypophosphite was not included. The pH values of the test solutions were adjusted by NH3d H2O to fix at 11. The weight loss increases linearly with the immersion time increasing of magnesium alloys in the Na2CO3, Na2 B4O7, and CH3COONa test solutions. It is revealed in Fig. 1 that the corrosion rates were constant throughout the examined immersion time. As recognized from the slope of each solid line in Fig. 1, corrosion rate in the test solution containing Na2CO3 buffer is the lowest among the three tested buffers. The obtained slopes are 0.015, 0.022 and 0.056 mg cm_2 min_1 for Na2CO3, Na2 B4O7 and CH3COONa buffers, respectively. These results can be explained in terms of dissociation constants of the corresponding acids, which are k 2=4.7_10_11 ( k 1=4.4_10_7 ) , k 2=1_10_9 (k1=1_10_4), and k=1.75_10_5 for H2CO3, H2B4O7 and CH3COOH, respectively. The second dissociation constant of a binary acid decides the buffer capability of the buffer. Obviously, the Na2CO3 buffer has the lowest cost and best buffer capability among the tested buffers. Fig. 2 shows the weight loss of the substrates versus immersion time in the test solutions with pH values at 9, 10 and 11, using Na2CO3 as the buffer. Corrosion of the specimens in non-buffered test solutions with pH values at 9, 10 and 11 was also investigated. The corresponding weight loss curves are shown in Fig. 2. All test solutions used for these experiments had compositions similar to those in the plating bath except that sodium hypophosphite was not included. The weight loss linearly changes with the increase of the immersion time in all cases shown in Fig. 2. Under the same pH value, the corrosion rate of the substrates in the buffer solution is obviously lower than that of the substrates in the non-buffered solution, as shown by the slopes of the curves in Fig. 2. This suggests that the buffer solution has a considerable effect on the corrosion rate of magnesium alloy. In both the Na2CO3 buffered and non-buffered test solutions, the corrosion rates of magnesium alloy decrease with the increase of the pH value. This indicates the weight-loss of the substrates is related to the reaction between the substrate metal and the hydrogen ions. But the corrosion reaction between the substrate metal and the hydrogen ions goes gradually on, because the low concentration of hydrogen ions is presented in the plating alkaline solutions. And then, the concentration of hydrogen ions is weakly decreased during the test progress. This leads to the constant corrosion rates in the short test time, which is shown in Figs. 1 and 2. At the same time, knowing that for Mg(OH)2 Ksp at 25 8C=8.9_10_12 at pH 9, [OH_]=10_5 M, most Mg2+ diffused into plating solution to form up to 10_2 M. At pH 11, [OH_]=10_3 M, the [Mg2+] couldn’t exceed 10_6 M, thus most Mg2+ formed Mg(OH)2 and stayed near the substrate. Mg(OH)2 could increase the adsorption energy barrier and reduce the corrosion rate. Therefore, higher pH resulted in lower corrosion rate. As to the Na2CO3 buffered solutions, for MgCO3 Ksp at 25 8C=10_15, in test solutions, [Na2CO3]N0.1 M, thus the possible [Mg2+]b10_14 M. This means that the driving force for Mg to form Mg2+ was very low. Instead of dissolving Mg, the CO3 2_ ion would bond or be adsorbed to the substrate surface to form local Mg—CO3 2_. In this case, the substrate surface area exposed to H2O or H+ was reduced a lot, 0 5 10 15 20 25 30 35 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 Na(CH3COO) Na2B4O7 Na2CO3 Weight loss/mg.cm-2 Time/min Fig. 1. The variation of weight loss of magnesium alloy in test solutions with different buffers. 0 5 10 15 20 25 30 35 0 1 2 3 4 5 solution pH=9 pH=10 pH=11 pH=9 pH=10 pH=11 Weight loss/mg.cm-2 Time/min in non-buffered solution in Na2CO3 buffered Fig. 2. The variation of weight loss of magnesium alloy in test solutions with different pH values. 3012 J. Li et al. / Surface & Coatings Technology 200 (2006) 3010–3015 leading to lower corrosion rates. The pKa2 for Na2CO3 is 10.33, at pH lower than 10.33 some CO3 2_ ions formed HCO3 _. Reaction Mg+2HCO3 _=MgCO3+H2 potentially existed. At pH higher than 10.33, [HCO3 _] is negligible. Therefore in Fig. 2, we can see that the corrosion rate at pH 11 was not reduced as much, compared the rate at 10. H2B4O7 and CH3COOH don’t have such advantages. 3.2. The effects of plating parameters on coatings The coating rate, surface appearance, and adhesion of the coatings at different concentrations of Na2CO3 buffer are listed in Table 4. The critical load (LC) was measured under progressive loading conditions, which can be used to accurately characterize the adhesion strength of the deposit/ substrate system [13]. The adhesion between the coatings and substrates decreases obviously with the increase of the concentration of Na2CO3. Surface appearance of the plating coatings becomes gradually shining with the increase of the Na2CO3 concentration. Grave corrosion of the substrates was found in the non-buffered plating bath. The growth rate of the coatings noticeably increases with the increase of the Na2CO3 concentration. Considering the combination of growth rate, surface appearance, and adhesion of the coatings, the optimum concentration of the Na2CO3 buffer was determined to be 30 g L_1.With this concentration, the purpose of adding Na2CO3 in plating bath is commendably achieved. In the research, it was found that the pH value of plating bath had a considerable effect on the growth rate and the surface appearance of the coatings. The hydrogen ions in plating bath were not only astricted by the CO3 2_ ions dissociated from the buffer Na2CO3, but linked with the OH_ ions. When the pH value of the plating bath was below 8.5, point corrosion or dark gray coatings were obtained and the coating growth rate was low. When the pH value of the plating bath was above 11.5, the adhesion between coatings and substrates were deteriorated, although the growth rate and the surface appearance of the coatings were satisfying. During the electroless plating, the pH value of the plating bath was monitored with a pHS-25C model of precision pH/mV meter. In this research, the preferred pH range of the plating bath for electroless plating on magnesium alloy is 8.5–11.5. Table 4 Coating rate, surface appearance and adhesion of the coatings obtained from the plating bath with different amounts of Na2CO3 Concentration of Na2CO3 (g L_1) Coating rate (Am/h) Surface appearance LC (N) 0 – Grave corrosion – 10 12.32 Point corrosion 81 20 16.41 Dark gray 76 30 18.32 Shining 73 40 18.91 Shining 61 50 19.26 Shining 51 20 30 40 50 60 70 13 14 15 16 17 18 19 20 The coating thickness/ìm The trisodium citrate dihydrate content/g.L-1 Fig. 3. Relationship between the coating thickness and the trisodium citrate dihydrate concentration. 30 40 50 60 1000 2000 3000 4000 5000 6000 7000 8000 Intensity 2è /( o ) Fig. 4. XRD patterns of the electroless plating coating. Fig. 5. Surface morphology of a plating coating. J. Li et al. / Surface & Coatings Technology 200 (2006) 3010–3015 3013 Fig. 3 shows the variation of coating thickness on magnesium alloy at same plating time as a function of the trisodium citrate dihydrate concentration at constant temperature and pH. The coating thickness decreases with the increase of the trisodium citrate dihydrate concentration. According to De Minjer and Brenner’s explanation [11], at low concentrations the low adsorption of ligand on the catalytic surface of the substrate accelerates the plating reaction. At higher concentration, there is a high adsorption of ligand on the surface, which slows down the plating reaction. But when the concentration was below 20 g L_1, the plating bath became destabilized and nickel precipitate was observed. 3.3. Properties of the plating coatings from nickel sulfate The coating obtained under optimized bath composition was probably preferentially crystallized (see Fig. 4). The only and strong diffraction observed in the XRD spectrum corresponds to the (111) peak of nickel. Fig. 5 shows the surface morphology of the plating coating. The surface is optically smooth and of low porosity. No obvious surface damage was observed. The compositions of the plating coating were determined to be 5.39 wt.% P and 94.61 wt.% Ni by energy dispersive X-ray spectroscopy. Fig. 6 shows the cross section of an electroless plating coating. The coating has a good adhesion to the substrate and no cracks or holes were observed. Fig. 7 shows the curve of the Ni–P coating free corrosion potential with time. After the sample was immersed in 3.5 wt.% NaCl solution at room temperature for 2 h, the free corrosion potential of the coated magnesium alloy approached to about _0.4 V. The steady-state working potential of magnesium electrode is generally about _1.50 V, although its standard potential is _2.43 V [14]. This indicates the improved corrosion resistance of the plating coatings prepared in this research, compared with the bare alloy. The adhesion between the coatings and the substrates was evaluated by means of quenching and the scratch test. The plated specimens were heated at a temperature of 250 8CF10 8C for 1 h, and then quenched in the cold water. This process was repeated for 20 times on each specimen. No discoloration, cracks, blisters, or peeling was observed [12]. For the scratch test, the critical load (LC) of 73 N was found for the coatings obtained in the optimized bath composition and parameters. These results suggest the excellent adhesion of the plating coating to the substrate. 3.4. Proposed mechanism of the electroless plating nickel Even under the same pH value, the magnesium alloy exhibits better corrosion resistance in the Na2CO3 buffered plating solution than in the non-buffered plating solution. Fig. 6. Cross section view of an electroless plating coating. 0 1 2 3 4 5 6 7 8 -0.46 -0.44 -0.42 -0.40 -0.38 -0.36 -0.34 -0.32 -0.30 ESCE/V × 103, time/s Fig. 7. Curve of the Ni–P coating free corrosion potential with time. 3014 J. Li et al. / Surface & Coatings Technology 200 (2006) 3010–3015 Fig. 8 gives a simple model to explain this phenomenon. Large amount of H2 gas is produced in the electroless plating process. Most of the H+ ions are taken out by the H2 gas bubbles and combine with the CO3 2_, to form HCO3 _. Therefore, a very thin layer of dilute H+ solution is formed near the surface of substrate. The Ni2+ ions react with the magnesium atoms to form the autocatalysis nickel, which leads to the deposition of the Ni–P coating. If the concentration of the CO3 2_ ions is low, more H+ ions will be free and erode the thin Ni–P coating and the substrate. If the concentration of the CO3 2_ ions is much higher, the H+ ions concentration in the thin dilute H+ solution layer near the substrate surface will be much lower. Therefore almost no corrosion process will exist in the interface between the Ni–P coating and the su