本文選題：陶瓷結(jié)合劑 + cBN　； 參考：《河南工業(yè)大學(xué)》2017年碩士論文

【摘要】：陶瓷結(jié)合劑cBN磨具因?yàn)榫哂心透邷亍⒆凿J性好、導(dǎo)熱性好等優(yōu)良的性能而在航空航天、汽車零部件的加工等領(lǐng)域得到廣泛應(yīng)用。然而,在使用過程中它卻存在很多亟待解決的關(guān)鍵問題,這些問題主要根源于傳統(tǒng)燒結(jié)的溫度梯度和陶瓷結(jié)合劑的脆性。本文重點(diǎn)從燒結(jié)方式、添加劑(納米碳化釩、納米碳化鉻及其復(fù)合粉末)以及輔助磨料(綠碳化硅)三個(gè)方面,探討了陶瓷結(jié)合劑cBN磨具的制備方法與性能改善途徑。主要采用萬能材料試驗(yàn)機(jī)、差熱膨脹儀、掃描電子顯微鏡、X射線衍射儀等檢測(cè)手段,以Na_2O-CaO-B2O3-Al_2O_3-SiO_2體系為陶瓷結(jié)合劑基礎(chǔ)體系,首先較為系統(tǒng)的探討了微波燒結(jié)對(duì)陶瓷結(jié)合劑及cBN磨具性能的影響,確定了微波燒結(jié)的最佳工藝參數(shù);然后,研究了三種納米過渡金屬碳化物及其添加量對(duì)陶瓷結(jié)合劑cBN磨具的性能影響;最后,探討了綠碳化硅作為輔助磨料對(duì)微波燒結(jié)制備陶瓷cBN磨具的作用效果。結(jié)果表明:(1)微波燒結(jié)法可以在較低的溫度(800℃,比傳統(tǒng)燒結(jié)溫度低200℃左右)下實(shí)現(xiàn)陶瓷結(jié)合劑的燒成,此時(shí)結(jié)合劑的抗折強(qiáng)度為116.12MPa,相比于傳統(tǒng)燒結(jié)試樣的最大抗折強(qiáng)度值(102.89MPa)提高了12.9%;磨具試樣的最佳微波燒成溫度為850℃(比傳統(tǒng)燒結(jié)溫度低150℃),此時(shí),其抗折強(qiáng)度(69.53MPa)比傳統(tǒng)燒結(jié)法制得試樣的強(qiáng)度值(57.21MPa)提高了21.5%;(2)在微波燒結(jié)條件下,添加1.0wt.%的納米碳化釩后,陶瓷結(jié)合劑及cBN磨具試樣的綜合熱力學(xué)性能達(dá)到最佳值。其中,結(jié)合劑的平均線膨脹系數(shù)從6.63×10~(-6)℃~(-1)降低到5.83×10~(-6)℃~(-1)(降低了12.1%),流動(dòng)性從108.8%增大到144.0%(增大了35.2%),磨具試樣的氣孔率從25.53%增大到26.80%(增大了1.27%),抗折強(qiáng)度從69.53MPa增大到79.75MPa(增大了14.7%);(3)在微波燒結(jié)條件下,添加1.5wt.%的納米碳化鉻后,磨具試樣的熱力學(xué)性能達(dá)到最佳值。其中,結(jié)合劑的平均線膨脹系數(shù)從6.63×10~(-6)℃~(-1)降低到5.57×10~(-6)℃~(-1)(降低了16.0%),流動(dòng)性從108.8%增大到165.2%(改善了56.4%),磨具試樣的抗折強(qiáng)度從69.53MPa增大到96.27MPa(改善了38.5%);(4)在微波燒結(jié)條件下,添加4.0wt.%的納米碳化釩/鉻復(fù)合粉末后,磨具試樣的綜合性能較好。其中,陶瓷結(jié)合劑的平均線膨脹系數(shù)從6.63×10~(-6)℃~(-1)降低到4.56×10~(-6)℃~(-1)(降低了31.2%),流動(dòng)性從108.8%增大到158.8%(增大了50%),抗折強(qiáng)度變化幅度較小(改善了4.6%)。此外,磨具試樣對(duì)模具鋼的磨削性能有所改善,其磨削比增大了26.0%,平均摩擦系數(shù)減小了38.4%。(5)以綠碳化硅代替白剛玉作為輔助磨料后,磨具試樣的最佳燒結(jié)溫度降低了50℃,抗折強(qiáng)度從69.53MPa提高到80.30MPa(提高了15.5%),硬度從75.5HRB增大到95.0HRB(增大了25.8%)。但是,其磨削性能卻有所降低。
[Abstract]:Ceramic bond cBN abrasives have been widely used in aerospace, automobile parts processing and other fields because of their excellent properties such as high temperature resistance, good self-sharpness, good thermal conductivity and so on. However, there are many key problems to be solved in the process of application. These problems are mainly due to the traditional sintering temperature gradient and the brittleness of ceramic binders. In this paper, the preparation and performance improvement of ceramic bond cBN abrasives are discussed from three aspects: sintering method, additives (nano-vanadium carbide, nano-chromium carbide and its composite powder) and auxiliary abrasive (green silicon carbide). By means of universal material testing machine, differential thermal expansion instrument, scanning electron microscope and X-ray diffractometer, the Na_2O-CaO-B2O3-Al_2O_3-SiO_2 system is used as the base system of ceramic bond. Firstly, the effects of microwave sintering on the properties of ceramic bond and cBN abrasive are systematically discussed, and the optimum technological parameters of microwave sintering are determined. The effects of three nano-transition metal carbides and their addition on the properties of ceramic bond cBN abrasives were studied. Finally, the effect of green silicon carbide as an auxiliary abrasive on the preparation of ceramic cBN abrasives by microwave sintering was discussed. The results show that the sintering of ceramic binder can be realized by microwave sintering at lower temperature of 800 鈩，

本文編號(hào)：1903868