The film-forming, friction and wear properties of a range of model and commercial ashless P and P/S antiwear additives have been studied. A method has been developed for removing the tribofilms formed by such additives in order to effectively quantify mild wear. In general the P/S additives studied formed thinner tribofilms but gave lower wear than the S-free P ones. In extended wear tests, three P/S additives gave wear as low, or lower, than a primary zinc dialkyldithiophosphate (ZDDP). For almost all lubricants tested the wear rate measured in short tests was considerably higher than that in long tests due to the greater contribution of running-in wear in the former. This highlights the importance of basing antiwear additive choice on reasonably long tests, where running-in becomes only a small component of the wear measured. It has been found that for both P and P/S ashless additives the addition of oil-soluble metal compounds based on Ti and Ca boosts tribofilm formation and can lead to very thick films, comparable to those formed by ZDDP. However, this thick film formation tends to be accompanied by an increase in mixed friction and also does not appear to reduce wear but may even increase it.

中文翻译：

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某些含磷抗磨添加剂的摩擦膜形成，摩擦和减摩性能

研究了各种型号和市售的无灰P和P / S抗磨添加剂的成膜，摩擦和磨损性能。为了有效地量化轻度磨损，已经开发了一种去除由这种添加剂形成的摩擦膜的方法。通常，研究过的P / S添加剂可形成更薄的摩擦膜，但磨损率低于不含S的P膜。在延长的磨损测试中，三种P / S添加剂的磨损与伯二烷基二硫代磷酸锌（ZDDP）相同或更低。对于几乎所有测试的润滑剂，由于前者的磨合磨损贡献更大，因此在短时间测试中测得的磨损率明显高于长时间测试中的磨损率。这突出了在合理的长时间测试中选择抗磨添加剂的重要性，在这种情况下，磨合仅是所测磨损的一小部分。已经发现，对于P和P / S无灰添加剂，基于Ti和Ca的油溶性金属化合物的添加促进了摩擦膜的形成并且可以产生非常厚的膜，这与由ZDDP形成的膜相当。但是，这种厚膜形成往往伴随着混合摩擦的增加，并且似乎没有减少磨损，甚至可能增加磨损。