| Since micro-nanometer lubricating material and technique possess significant meaning to machine parts in wear repairing, prolonging working life and reducing energy consuming, it is an increasing tendency for scientists to design novel lubricating system. But existed problems, such as higher cost to prepare nano-particulates, unstable decentralization, lower composition of elementary metals in repairing coatings, more thin coating thickness (as decades nanometers) and complicated repairing techniques and so on, restricted its application. This paper focus on researching and developing a serious of novel lubricants with activating method, which contained micro-nanometer soft metals, such as Sn, Zn, Al, Al-Sn, Al-Sn-Zn, Zn-Sn, In-Zn-Sn and so on. These new types of lubricants were in characteristics of simplifying preparing techniques, repairable to relatively serious worn surface, good lubricating, friction-reducing and anti-wear performance, and environment friendly properties. Based on steel-steel and steel-copper tribo-pair, their repairing behaviors and tribological properties were investigated. By means of X-ray Photoelectron Spectrum (XPS), Auger Electron Spectrum (AES) and Scanning Electronic Microscope (SEM), cooling quenching and nick, extend, bend testing, and Nano Mechanical Test Instruments, the composition, thickness, combining intensity, contact stress of the coatings were researched separately. The friction repairing action mechanism of the carried out lubricants were studied and analyzed. Furthermore, the applications foreground of lubricants used in mechanical transmission were also evaluated with frame testing. The results were as follows:Activated Nano-Tin lubricant was carried out with activating techniques and mechanical preparation, its particles diameters were below 100nm. The Nano-Tin lubricant was used for copper surface friction test. SEM showed that the repairing coating with thickness about 10μm-20μm has been created on the copper surface by the repairing lubricant under the action of mechanical and friction force. The coating was combined tightly with the substance. XPS and AES analytical results indicated that the coating contained rich Sn and its concentration of atom percentage of Sn could reach to 90% at tiptop. This explained why the coatings possess excellent friction-reducing and anti-wear capabilities. The test also proved the important effect of activated additives on repair quality.No.32 basic oil was replaced by No.00 semi-liquid grease to resolve dispersibilities instability and sedimentation of the additive particulates in the lubricating oil. The prepared semi-grease contained 20% activated micrometer Tin, which formed 20μm Sn coating on the cooper surface under friction, always displayed negative wearing characters under various loading conditions, its friction-reducing and anti-wear properties were average higher 32%,23% and 148%,423% separately than traditional anti-wearing lubricants of 3%ZDTP and 3% chlorinated paraffin.Zn kind and Zn-Tin Compound activated lubricating grease were developed that possess good repairing character and tribological performance. Zn coating with 10μm thickness and Zn-Sn coating with 20μm thickness were created on the copper substance under friction. Integrating effect of Zn-Sn let its friction-reducing and anti-wear characters exceeded than Zn grease evidently under various loading conditions.A1 kind of lubricants were explored that could create Al-Sn coating with 15μm thickness and Al-Sn-Zn coating with 25μm thickness on copper substance under friction. Al, Sn and Zn distributed on entire coatings and seeped plated into the copper base. It implied the mutual fitting performance and synergisms of activated additives of Al-Sn and Al-Sn-Zn, and the good matching capabilities with tribo-pair.Difficult problem that additive was hard to form repairing coating in considerable thickness on steel surface was solved. Through integration effect and synergisms under the action of several additives, the effective repairing lubricants with activated Zn-Sn and In-Zn-Sn were carried out. The worn steel surface was repaired efficiently. The coating's thickness of Zn-Sn and In-Zn-Sn were 20μm and 30μm separately. The steel-steel tribo-pair after lubricating repairing was always displayed negative wear situation under various loads and rotating conditions, and low friction coefficient characteristic was showed stably at high rotation speed.The combination intensity of the coating was tested through cooling quenching and nick test. The coatings after test there were no crinkling, bullate, avulsion and break off, the combination between the coating and base was eligibility. The affecting to coatings when sample under tension and bending were reviewed. The concretion capability between the coating and base was good under 3.2-5.6mm of bending distortion and 2.7-3.6mm of tension displacement. The micro mechanical properties were analyzed by nano-indentation technique. The surface contact stress of the repaired teeth in the steel-steel spur gear transmission and steel worm against copper wormgear transmission were calculated and analyzed. The study indicated that the exterior performance of those repaired surface was optimized and contacting stress on teeth surface could depress obviously.On the basis above, the frame testing was performed on the WD33-20 type of wormgear reducer with the carried out 25Sn15Zn5In grease and No.00 contrast grease separately. Worn occurred on the teeth surface of worm and wormgear when use No.00 lubricating grease with no additives. When replaced by 25Snl5Zn5In lubricants, the Fe and Cu concentration in the grease reduced sharply. It means that the abrasion of worm and wormgear has been controlled effectively, and the damnifyed area on the teeth surface has been repaired basically. The mechanical efficiency of the reducer was advanced greatly. It was showed that the developed repair lubricants possess potential application foreground.
|
PDF Full Text Request