镍磷合金镀层防变色性能初探

采用正交试验和条件试验，筛选出了一种以植酸、苯甲酸钠、钼酸钠和EDTA为基本组成的镍磷合金抗蚀防变色剂。通过孔隙率测定、18％～20％盐酸点滴实验、10％氯化钠浸泡实验和阳极极化曲线测试等实验，对镍磷合金层的抗腐蚀性能进行了研究。     

Effects of phosphorus addition on the magnetic properties of sintered Fe-50 wt.% Ni alloys

Phosphorus was added to Fe-50 wt.% Ni in the form of a coated composite powder via an electroless plating process. Addition of phosphorus to Fe-50 wt.% Ni facilitated increases in density and grain size, both of which were beneficial to magnetic performance. Because of the homogeneous distribution of phosphorus in the powder, the optimal phosphorus addition was much lower than for those using Fe₃P as the phosphorus precursor. The optimal phosphorus addition was close to its maximum solubility in Fe-50 wt.% Ni (about 0.5 wt.%), above which precipitation of excessive phosphorus in the form of iron nickel phosphide, (Fe,Ni)₃P, effectively degraded the magnetic properties of Fe-50 wt.% Ni. Without the addition of phosphorus, good magnetic properties could be achieved only when the sintering temperature was high enough (>1200 °C) to result in a high sintered density and large grains in the sintered structure.     

New high-temperature copper alloys

New high-strength, high-temperature Cu-Ni-Si alloys have been developed using additions of Cr, Zr, and/or Ti. These new alloys remain as precipitation hardenable as the base alloy, but the main strengthening phase may be different than Ni₂Si (e.g., Cr₂Ti). Substantial increases in mechanical strength were observed at both room and high temperature (773 K) when additions of Cr+Zr+Ti and Cr+Zr were made. Industrial testing of these alloys indicated a sevenfold increase in the lifetime of lateral blocks in continuous casting equipment of copper alloys.     

Nickel Electroplating

NICKEL ELECTROPLATING has been practicallyused for decades.There is an unknown part in theplating,although this is easy to plate.Applications ofthe plating are described from the practical viewpoint.Purpose of Nickel Electroplating(1)Decorative,and corrosion resistanceNickel electroplating is deposited on iron,cupper,zinc and aluminum substrate etc.,and chromiumplating is usually deposited on nickel plating.Hexavalent chromium plating has an important effecton the corrosion resisitan…     

换热器表面预处理及防腐工艺

石化换热器许多设备都由碳钢制作,需要涂镀渗防腐,为保证防腐层质量,需要进行严格的表面预处理。概述了机械与化学表面预处理及相关的防腐工艺。     

化学还原法制备导电涂料用片状超细铜粉的研究

以CuSO4·5H2 O为原料 ,抗坏血酸为还原剂 ,NH3 ·H2 O为络合剂 ,将络合剂在反应温度加到CuSO4·5H2 O溶液中 ,再加入还原剂 ,制备了粒径分布为 1～ 10 μm的片状铜粉。探索与分析NH3 ·H2 O的用量、反应温度和CuSO4浓度对铜粉形貌及产率的影响。结果表明 :络合剂的使用是制备片状超细铜粉的关键 ,其与Cu2 + 形成络合物 ,减少溶液中游离Cu2 + 的浓度 ,控制铜的生成速度 ,并影响铜的成核和生长 ,最终形成片状铜粉。     

四官能环氧树脂的合成以及在覆铜板中的应用

对四官能环氧树脂[1,1,2,2-四(对羟基苯基)乙烷四缩水甘油醚]的合成与改性及在覆铜板中的应用作了初步探讨,并对其屏蔽紫外线与产生荧光的机理作用作了简单阐述。     

采用“两级跳间隙镀”电源的无氰碱铜工艺研究

回顾了对无氰碱铜研究历史中的经验教训。在大量试验基础上，提出了一种706无氰碱铜工艺。对配位剂的恰当选择、组合及工艺条件控制，能将临界活化电流密度降得很小，使钢铁件上能在宽JK范围内直接预镀铜而取得良好结合力。用开发的“冲击镀加间隙镀两级跳自动电源”，更有利于提高结合力及提高抗阴阳离子杂质影响能力。加入适量硝酸钾能降低液温并提高允许JK，有利于无氰加厚镀铜及复杂管件装饰镀。     

硫酸铜灭藻影响因素的试验研究

目的通过对硫酸铜灭藻影响因素的试验研究,确定出硫酸铜灭藻的最佳工况条件.方法以叶绿素a法作为检测方法,通过烧杯试验,确定处理含藻水的最佳硫酸铜投加量、接触反应时间、pH等参数.结果硫酸铜最佳投加量为1.5 mg/L;硫酸铜适宜的接触反应时间为8～12 h;pH值6.6左右时,硫酸铜藻类去除率较高,pH值＞9时,藻类去除率显著降低.结论 pH值对硫酸铜灭藻效果的影响较大;温度对硫酸铜灭藻有一定的影响;水中还原物质浓度对硫酸铜灭藻影响较小;藻类浓度不同对硫酸铜灭藻效果有一定的影响.     

连续电镀锌镍合金的研究

提出了一种高氯化铵弱酸型镀液体系连续电镀锌镍合金工艺，研究了m(Ni^2 )/[m(Ni^2 ) m(Zn^2 )]、氯化铵浓度，电流密度、温度、PH值对镀层镍含量的影响，推导出连续镀的镀速计算公式，采用此工艺可获得外观良好、镍含量在13％－15％的锌镍合金镀层。