铵盐镍基电镀金刚石钻头的电化学机理研究及应用

Study and Application on the Electrochemical Mechanism of Matrix Depositing of Nickel-based Electroplated Diamond Bit with Ammonium Salt

摘要:

以微机控制电化学分析系统对铵盐镍基胎体镀层的电化学机理进行研究，试验了硫酸镍用量、氯化铵用量、镀液温度和镀液的pH值对镍沉积的影响，结果表明保持镀液适当高的pH值、略低的温度和加入氯化铵，可使镍沉积的极化增大，从而使镀层晶粒变小，结晶致密，且氯化铵的加入没有改变阴极过程的控制步骤。在NiSO4·6H2O 280 g/L，NH4Cl 19 g/L，H3BO3 35 g/L，十二烷基硫酸钠0.1 g/L；镀液温度45 ℃±1 ℃，pH值5.2，电流密度3.6 A/dm2条件下电镀φ41/27 mm室内钻头，钻进可钻性Ⅷ级的绢云母化含石英斜长石玢岩，钻进时效平均达到1.94 m/h，钻头的磨损约为0.092 mm/m，与普通镍-钴胎体钻头的使用寿命相差不大；但其钻进时效要比镍-钴胎体钻头高0.18 m/h，即约高10%，为野外生产试验提供了试制钻头的可靠资料和经验。

Abstract:

Test on the electrochemical mechanism of nickel depositing in ammonium bath with computer aided electrochemical workstation, the experiments were made on effect to nickel deposition by concentration of nickel sulfate & ammonium chloride and plating bath temperature & pH value. The results indicated that the cathodic polarization of matrix depositing increased by the addition of ammonium chloride with higher pH and lower temperature. This was beneficial for the refinement of nickel crystal and the electrode process was not affected by adding ammonium chloride. Indoor drilling tests were used to the selected bath formula by the electrochemical experiments. Bit of φ41/27mm was plated with the formula of 280g/L nickel sulfate, 19g/L ammonium chloride, 35g/L boric acid and 0.1g/L sodium dodecyl sulfate at pH value of 5.2, cathodic current density of 3.6A/dm2 and temperature of 45℃±1℃, the average penetration rate was 1.94m/h and wearing rate 0.092mm/m while drilling in sericitization quartz plagioclase porphyrite of drillability grade Ⅷ; the service life was similar to the conventional nickelcobalt electroplated bit, but the penetration rate was 0.18m/h higher.