A tribological study of a novel pre-treatment with linseed oil bonded to mercaptosilane treated aluminium
A tribological study of a novel pre-treatment with linseed oil bonded to mercaptosilane treated aluminium
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DOI：
10.1016/s0257-8972(02)00784-3
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发表时间：
2003-03-24
影响因子：
5.4
通讯作者：
Sundell, PE
中科院分区：
文献类型：
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作者：
Bexell, U;Olsson, M;Sundell, PE
在金属板材成形过程中，润滑剂是必要的，以防止磨损，即材料从金属板材转移到工具表面并控制摩擦。如今，越来越多地使用干润滑剂来解决这个问题。其中，多功能涂料，通常称为永久涂料，通常基于有机树脂，是一种润滑剂，无需额外润滑即可提高成型性，在处理和运输过程中提供腐蚀保护、防指纹和防刮擦，最后作为涂漆前的预处理。随着人们对环境和人类健康的日益关注，在金属基材的表面工程中开发新型环保预处理方法变得非常重要。这主要是由于行业中经常使用的铬基表面预处理剂具有毒性和致癌性。在过去的十年中，简单的溶液浸渍硅烷基预处理已成为替代当前使用的金属预处理的有希望的候选者。硅烷膜可以提供良好的腐蚀防护性能，但通常太薄而无法防止成型操作中的磨损。由于多种因素，最近人们对在表面工程中使用植物油产生了新的兴趣。植物油是可再生资源，现代技术可以生产更明确和纯净的油，并且可以通过现代作物开发技术改变脂肪酸含量。通过正确选择金属表面的硅烷预处理，可以将植物油偶联到表面并提供所需的润滑性能。在本文中，铝板经过巯基硅烷预处理，然后附着植物油。硅烷和油之间的偶联是通过使用紫外线辐射的光诱导硫醇-烯反应获得的。使用改进的划痕测试评估不同工艺参数对摩擦和磨损行为的影响。使用扫描电子显微镜（SEM）、俄歇电子能谱（AES）和接触角测量来表征沉积表面薄膜及其摩擦学行为，即失效机制。所得结果表明，不饱和植物油已通过硫醇-烯反应与硫醇基团反应，形成表面膜。此外，结果表明薄膜的厚度对于摩擦学特性很重要，即太薄的层（在本工作中小于 25 A）会导致高摩擦和严重的粘着磨损。然而，通过对沉积的植物油进行适当的热处理，可以产生具有增强的承载能力的较厚的层。最后，结果表明，厚的（本研究中超过 200 埃）硅烷薄膜在接触滑动接触时对脆性断裂很敏感。 (C) 2002 Elsevier Science B.V. 保留所有权利。
In sheet metal forming processes, lubricants are necessary in order to prevent galling, i.e. material transfer from the sheet metal to the tool surface and to control friction. Today, dry lubricants are increasingly being used for solving this problem. Among these, multifunctional coatings, often referred to as permanent coatings, normally based on organic resins, are lubricants which have the potential to increase the formability without additional lubrication, give corrosion protection, fingerprint and scratch resistance during handling and transport and finally, serve as a pre-treatment before painting. With increasing concern about the environment and human health it is important to develop new environmentally friendly pre-treatments in the surface engineering of metal substrates. This is mainly due to the toxic and carcinogenic properties of the chromium based surface pre-treatments frequently used in the industry. During the last decade, simple solution-dip silane based pre-treatments have emerged as promising candidates for the replacement of currently used pre-treatments of metals. A silane film can give good corrosion protection properties but is often too thin to prevent galling under a forming operation. A renewed interest for using vegetable oils in surface engineering has appeared lately due to several factors. Vegetable oils are renewable resources, modem technology can produce more well defined and pure oils, and the fatty acid content can be altered with modern crops development techniques. With the proper choice of silane pre-treatment of a metal surface, a vegetable oil can be coupled to the surface and give the desired lubrication properties. In this paper, aluminium sheets have been pre-treated with a mercapto silane after which a vegetable oil has been attached. The coupling between the silane and the oil was obtained through a photoinduced thiol-ene reaction using UV-radiation. The influence of different process parameters on the friction and wear behaviour was evaluated using modified scratch testing. Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and contact angle measurements were used to characterise the as-deposited surface films and their tribological behaviour, i.e. failure mechanisms. The results obtained show that the unsaturated vegetable oil has reacted with the thiol groups via the thiol-ene reaction forming a surface film. Also, the results show that the thickness of the films is of importance for the tribological characteristics, i.e. a too thin layer (less than 25 A in the present work) results in high friction and severe adhesive wear. However, a thicker layer with enhanced load carrying capacity can be produced with a proper heat treatment of the deposited vegetable oil. Finally, the results show that thick (more than 200 Angstrom in the present work) silane films are sensitive to brittle fracture when exposed to a sliding contact. (C) 2002 Elsevier Science B.V. All rights reserved.