Tham khảo tài liệu 'lubricants and lubrication part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 18 I 2 Lubricants in the Tribological System ing lubricant film either minimizes or eliminates this problem. Machine elements which are subjected to periodically severe loads in the contact zone are particularly prone to this type of damage. Erosion Erosive wear which is a loss of material from a solid surface occurs during the impingement on a surface by a fluid containing solid particles. Fretting The contacting partners are part of a system which oscillates at small amplitude. Most of the previously mentioned types of wear are included in fretting wear and this explains why fretting wear is seen as a separate form. Besides mechanical components tribochemical reactions play an important role. Oxidation creates layers and fretting wear is sometimes known as fretting corrosion. Fretting wear can be avoided if suitable surface-active additives are added to lubricants especially as pastes for threaded fasteners . Cavitation Materials can be damaged by imploding gas and vapor bubbles entrained in lubricating oils or hydraulic fluids. In systems which carry lubricants the elimination of dragged-in air low boiling point substances or the use of surface active components scale-down the gas bubbles and thus reduce cavitation. The condition of surfaces effected by cavitation can be further damaged by corrosion. This process can be controlled by the use of specific inhibitors. Types ofWear There are several criteria which could be used to classify the different types of wear. For example according to the types of kinematic friction which lead to wear sliding wear rolling wear fretting wear according to wear mechanisms adhesive wear abrasive wear tribochemical wear or according to the shape of the wear particle. There is also highly specialized wear terminology for different lubricant applications this is oriented to the geometry of the various bearing faces . clearance and crater wear in the field of chip-forming tools . The Wear .
