【作者】 郑莲；

【导师】 方莉俐；

【作者基本信息】 中原工学院 ， 凝聚态物理， 2014， 硕士

【摘要】 采用化学镀预镀导电层、电镀加厚的方法，实现金刚石的表面金属化。利用扫描电镜（SEM）、X射线衍射仪（XRD）、能谱仪（EDS）、金刚石单颗粒抗压强度测定仪及冲击韧性测定仪等检测手段，研究了镀液成分、工艺条件、增重率对镀覆金刚石的形貌、物相、抗压强度及冲击韧性值的影响。通过对金刚石表面金属化基本问题的研究，得到以下结果：(1)化学镀液各成分对镍的沉积速率有一定影响。氯化镍浓度低于25g/L时，沉积速率随其浓度的增加而增大，氯化镍浓度高于25g/L时，沉积速率随其浓度的增加而降低；次亚磷酸钠浓度低于24g/L时，沉积速率随其浓度的升高而增大，次亚磷酸钠浓度超过24g/L时，沉积速率随其浓度的升高而下降；琥珀酸钠浓度低于18g/L时，沉积速率随其浓度的升高而增大，琥珀酸钠浓度超过18g/L时，沉积速率随其浓度的升高而下降。(2)化学镀工艺条件对镍的沉积速率有很大影响。温度低于70℃时反应无法正常进行，温度处于70~80℃之间时，沉积速率随温度的升高而增大，温度超过80℃时，沉积速率随温度的升高而下降，且随着时间的延长，镀液出现了不稳定的现象，镀液变黑，镀槽壁和底部均出现了镍沉积层。搅拌速率低于200r/min时，沉积速率随搅拌速率的升高而增大，搅拌速率超过200r/min时，沉积速率随搅拌速率的升高而减小。(3)化学镀的镀层较薄，金刚石化学镀镍前后的平均单颗粒抗压强度基本不变，抗压强度方差随镍含量的升高而降低。(4)电镀金刚石表面粗糙度随镀层增重率的增大而增大；金刚石的抗压强度随增重率的增加而增加。(5)400℃的热处理对电镀金刚石的表面形貌没有影响。400℃热处理30min的电镀金刚石样品较未热处理样品的XRD图谱，金刚石和镍均出现了峰位蓝移的现象。经400℃热处理的镀覆金刚石，抗压强度随增重率的增加而增加，且同等增重率电镀金刚石的抗压强度较热处理前有略微增大。(6) NaCl是影响电镀液导电性的主要因素，NiSO4对电镀液的导电性基本没有影响。NaCl浓度处于5g/L到30g/L之间时，电镀金刚石的冲击韧性值随NaCl浓度的增大而增大，当NaCl浓度超过30g/L后，电镀金刚石冲击韧性值随NaCl浓度的增大而减小；NiSO4浓度介于100g/L和250g/L之间时，电镀金刚石的冲击韧性值随着NiSO4浓度的增大而提高。NaCl浓度和NiSO4浓度对电镀金刚石抗压强度基本没有影响。更多还原

【Abstract】 The metallization of diamond surface was prepared by means of electroless precoatand electroplate thickening. The testing method contains SEM, XRD, EDS, diamondsingle particle compressive strength tester, impact toughness test apparatus and so on, theeffects of the bath composition, technological conditions and the weight rate on themorphology, phase analysis, compressive strength and impact toughness value areinvestigated.Through the study of metallization on man-made diamond surface, meaningfulresults were found out as follows:(1) Each component of electroless plating solution has a certain effect on thedeposition velocity of Ni. The results show that the deposition velocity increased withincreasing of the concentration of NiCl2when the concentration was under25g/L, butwhen it was greater than25g/L, the deposition velocity decreased with increasing of theconcentration of NiCl2; the deposition velocity increased with increasing of theconcentration of NaH2PO2when the concentration was under24g/L, but when it wasgreater than24g/L, the deposition velocity decreased with increasing of theconcentration of NaH2PO2; the deposition velocity increased with increasing of theconcentration of C4H4Na2O4when the concentration was under18g/L, but when it wasgreater than18g/L, the deposition velocity decreased with increasing of theconcentration of C4H4Na2O4.(2)Technological conditions of electroless plating have a great effect on depositionvelocity of Ni. The results show that the reaction cannot proceed normally when thetemperature under70℃, the deposition velocity increased with increasing of thetemperature when the temperature was at70~80℃, but when it was greater than80℃, the deposition velocity decreased with increasing of the temperature, withthe continuous extension of time reaction, the solution appeared unstable and black, Niplating appeared on the wall and bottom of bath; the deposition velocity increased withincreasing of the stirring rate when the stirring rate was under200r/min, but when it wasgreater than200r/min, the deposition velocity decreased with increasing of thestirring rate.(3) Compared with the man-made diamond grain, the average compressive strengthof single nickel plated diamond grain is not obviously changed under the condition of thethin coating; the variance of the compressive strength with different content of Ni wasquite different, and it decreased with increasing of Ni.(4) The surface roughness of diamond is increased with the increase of weight rate,and the compressive strength of diamond is increased with the increase of weight rate.(5)The400℃heating has no effect on the surface morphologies ofdiamond.Compared with the sample before heat treatment, the phenomenon of blue shiftis discovered on the diamond and nickel under the condition of heating it to400℃andkeeping it for30min. The average compressive strength is greatly improved and it isincreased with the increase of weight rate, even it is a little increased after heat treatment.(6) NaCl is the main factor in influencing the electrical conductivity of platingsolution, and NiSO4has no effect on the electrical conductivity of plating solution. Theimpact toughness value of diamond increased with increasing of the concentration ofNaCl when the concentration was at5-30g/L, but when it was greater than30g/L, theimpact toughness value of diamond decreased with increasing of the concentration ofNaCl, the impact toughness value of diamond increased with increasing of theconcentration of NiSO4when the concentration was at100-250g/L. The concentration ofNaCl and NiSO4has no effect on the compressive strength tester of diamond.更多还原