The effects of heat treatment temperature and time on the hardness and the wear resistance of RE (rare earth)-Ni-W-P-PTFE-SiC and RE-Ni-W-P-SiC composite coatings have been studied, and the results indicate that the hardness of the composite coatings is lower and the mass loss (i.e., rate of abrasion) is higher in the as-deposited state. The hardness rises and the rate of abrasion decreases with increasing hea treatment temperature; the abrasion rate is lowest and the hardness is highest at 400℃. The hardness decreases and the rate of abrasion ncreaseswithafurtherriseinthetemperature. Thehardnessandthewearresistancebothincreasewithariseinheattreatment time,andthey reach their peak values after 2 h of heat treatment. The experimental results also show that the hardness of the coating decreases with an increase in PTFE quantity, and the wear rate diminishes correspondingly. X-raydiffractionindicates thatthestructureoftheas-deposited RE-Ni-W-P-PTFE-SiC composite coating is of amorphous status. © 2004 Elsevier B.V. All rights reserved.

Corrosion rate and anode polarization curves of electrodeposited RE-Ni-W-P-Sic-PTFE composite coating in various concentrations of phosphoric and ferric chloride were researched. The results show that corrosion rate of the composite coatings increases with the increasing concentrations of phosphoric and femc chloride, and reaches the maximum value when phosphoric concentration is 40% and ferric chloride concentration is 20% (mass fraction, the same below if not mentioned). Anode polarization curves of the composite coatings show that anode polarization current density of the composite coatings heat-treated at 200℃ or 500℃ is lower than that of other coatings heat-treated at 300℃ or 400℃, which displays that the composite coatings heat-treated at 200℃ or 500℃ have better corrosion resistance. Besides, corrosion resistance of the composite coating heat-treated at 500℃ is better than that as deposited and RE-Ni-W-P-Sic composite coating heat-treated at 400℃, and is also better than that of 316L stainless steel.

研究了RE-Ni-W-P-SiC复合镀层在10%HC1，10%FeCl3，10%H2SO4和40%H3P04等介质中的腐蚀行为。结果表明，以 Ni-W-P合金为基体的复合材料镀层在镀态或热处理条件 下，在硫酸、磷 酸、盐酸和氯化铁溶液中具有较好的耐蚀性，其耐蚀性优于316L不锈钢；RE-Ni-W-P-SiC复合镀层在硫酸和磷酸溶液中的耐腐蚀性更明显；RE-Ni-W-P-SiC复合镀层在硫酸和磷酸溶液中的腐蚀为缝隙腐蚀和晶间腐蚀，而在盐酸和氯化铁溶液中的腐蚀为点蚀和晶间腐蚀。

研制开发了一种新型的化学镀镍光亮剂。试验结果表明，光亮剂在化学镀镍过程中没有参与反应，却对磷的沉积起到了积极的催化作用，显著地提高了镀层中的磷含量；当光亮剂的加入量达到5～6mL/L时，镀层中的磷含量可提高到35.63%～39.03%，同时可得到全光亮的镍。磷合金镀层，有效地改善了镀层的表面质量，且出光速度快，镀液稳定可靠。通过扫描电镜和x射线衍射对高磷镍。磷合金镀层的分析表明，镀层为非晶态结构。显微硬度、磨损率以及耐蚀性测试结果表明，镀态下镍。磷合金镀层的硬度、耐磨性和在10％盐酸中的耐蚀性随着光亮剂的增加而降低。。

Cathodic dcpasition current density of the composite coatinqs increases rnhen SiC par-ticles and rure earth (RE) were added in the bath, which is profitable for Ni-W-P alloy to deposiLinthe cathod, forming Ni-W-P-SiC and RE-Ni-W-P-SiC composite coat-ings. On the contrary, the addztzono，PTFEin the bath decreases cathodic deposition current density of the coatinqs. The current density increases a little，when the amount of RE is 7-9g/l; howerrer, the current density increases greatly when the amorirrt of RE is increased to11-13g/l. But if the amount of RE is raised further, the current density decreases. Hardness and wear resistance of RE-Ni-W-P-SiC corrtpoHite coat-irtg have been studied, and the resttlts shovr that the hardness and wear resistcince of RE-Ni-W-P-SiC. composite coatzng invrense tvith increasing heat treatment tempera-ture, tnhich reach peak vatues at 400℃; while the hardness and wear resistance of the cuatiag decrease with the rise of heat treated temperature continuously.

讨论了Ni-W-SiC复合镀层与氮碳共渗复合强化的组织结构及性能。结果表明，氮碳共渗后复合镀层的硬度和耐磨性远高于未氮碳共渗的复合镀层。扫描电镜结果表明，在共渗处理中，复合镀层存在硬度梯度，且基体中的铁向复合镀层扩散，形成“钉扎效应”，显著提高了镀层与基体的结合力。X射线衍射表明，复合镀层经氮碳共渗后，产生很多新相，这些相的存在显著提高了复合镀层的硬嚏和耐磨性。

Co-Sb-HzO系电位-pH图表明。在锌粉置换唇鼻钴过程中，锑与钴形成盒属间化合物，从而提高了锌粉置换除钴的热力学推动力。扫描电镜观察及X射线衍射结果表明，锑与镍和钴的存在形式相同，进一步说明钴与锑形成金属间化合物，而锌则以碱式硫酸锌、氧化锌和金属锌的形式存在。