超分散稳定纳米ZnS的非水原位构筑及摩擦学性能

设计并合成了油溶性环烷酸锌和异氰酸酯类超分散稳定剂,采用原位构筑方法获得了非水纳米ZnS分散系,用冷冻蚀刻电镜对其进行了表征,用离心实验对其分散稳定性进行了考察.对纳米粒子的形成过程、分散稳定机理进行了阐述.用环块和四球摩擦试验机对纳米ZnS分散系的摩擦学性能进行了研究.结果表明:ZnS为40 nm的粒状颗粒,大小均匀,在介质中呈单粒子分散;纳米分散系经72 h普通离心和56 h非连续超离心均未发生沉降,表现出理想的分散稳定性;试验显示超分散稳定纳米ZnS的存在,能明显改善油样的抗磨减摩性能和承载能力.在试验范围内,添加的纳米ZnS的量越大,其抗磨减摩性能也越好,但当n-ZnS的质量分数大于0.25%时,其承载能力趋于稳定.

Nonaqueous In-situ Synthesis and Tribological Characteristics of Ultra-Dispersity-Stability ZnS Nanoparticles

The oil-soluble zinc naphthenate and isocyanate hyper-dispersion stabilizer were suc-cessfully synthesized. The ZnS nanoparticles(n-ZnS) were synthesized in-situ in liquid paraffin containing zinc naphthenate and hyper-dispersion stabilizer. The size, size distribution and con-glomeration behavior of n-ZnS in dispersion were observed by the freeze-etching replication transmission electron microscopy technique. Formation and dispersion stability mechanism of n-ZnS were investigated. The tests of normal and high speed centrifuge were used for evalua-ting the dispersion stability of n-ZnS. Tribological characteristics of the lubricants in the pres-ence and absence of n-ZnS were investigated by the block-on-ring and four ball tribo-test. The results show that the n-ZnS are grain shape with 40 nm size and single-particle-dispersion prop-erties, which didn't come into being sedimentation through 72 h centrifuge tests and 56 h in-termittent high speed centrifuge tests. The n-ZnS Nano-dispersion exhibited antiwear property as well as extreme pressure property. The tribological characteristics of oil samples take a turn for better with n-ZnS content adding in the range of experiment. And the extreme pressure properties are heading for stability when n-ZnS contents of oil samples are weight percent of 0.25%.