Search results

Ultra-high molecular weight polyethylene (UHMWPE) has an excellent performance and application value; however, as a tribological material, its main drawback is its poor performance under dry friction, impacting its ability to work in high-speed dry friction conditions. Modification of UHMWPE can be carried out to overcome these issues. A significant number of inorganic materials have been used to modify UHMWPE and provide it with good tribological performance. However, thus far, there has been no systematic investigation into the methodology of modifying UHMWPE. The authors take a quantitative approach to determine the structure tribo-ability relationship and basic principles of screening of inorganic compounds suited to modify UHMWPE.

The tribological properties of modified UHMWPE using a series of inorganic additives have been qualitatively studied by the authors’ research group previously. In this study, basic quantitative structure tribo-ability relationships (QSTRs) of inorganic additives for modifying UHMWPE were studied to predict tribological properties. A set of 15 inorganic compounds and their tribological data were used to study the predictive capability of QSTR towards inorganic additives properties.

The results show that the anti-wear and friction-reducing properties of these inorganic compounds correlate with the calculated parameters of entropy and dipole moment. Increased entropy and smaller dipole moment can effectively improve the anti-wear and friction-reducing ability of inorganic compounds as UHMWPE additives. Additives with larger molecular weight, lower hardness and lower melting and boiling points provide good tribological properties for UHMWPE. For inorganic compounds to act as UHMWPE additives, the chemical bond should be less covalent and have more ionic character.

Only 15 inorganic compounds and their tribological data were used to study the predictive capability of QSTR towards inorganic additives properties. If the samples number is more than 30, the other QSTR methodology can be used to study the modified UHMWPE, and the models finding can be more precise.

A QSTR model for modified UHMWPE has been studied systematically. While the results are not more precise and detailed, the model provides a new way to explore the modified UHMWPE characteristics and to reveal new insight into the friction and wear process.

Because the method of studying tribological materials is entirely different from others, the authors want to present the works and discuss it with colleagues.

The paper presents a new method to study the modified UHMWPE. A QSTR is used to study the tribology capability of compounds from calculated structure descriptors. This study uses the Hartree–Fock ab initio method to establish a QSTR prediction model to estimate the ability of 15 inorganic compounds to act as anti-wear and friction-reducing additives for UHMWPE.

This paper aims to investigate the effect of the Cu, Ni and Ag addition in Sn5Sb-based alloy on the mechanical properties and its mechanism.

The micro-indentation, creeping test of the Cu/Sn5Sb–0.5Cu–0.1Ni–0.5Ag/Cu and Cu/Sn–5Sb/Cu were conducted, and its microstructure was analysed. The scanning electron microscope and the metallographic microscope characterized the microstructure of the Sn5Sb–0.5Cu–0.1Ni–0.5Ag/Cu and Sn–5Sb/Cu joints.

The microstructure of Cu/Sn5Sb–0.5Cu–0.1Ni–0.5Ag/Cu is distributed with the fine (Cu,Ni)6Sn5 and Ag3Sn intermetallic compounds (IMCs), whereas the Cu6Sn5 and Sn3Sb2 in Cu/Sn–5Sb/Cu is larger and far more less. This investigation reveals that the addition of the Cu, Ni and Ag elements reinforced mechanical properties and provided a technical basis for the development of Sn–Sb alloy with good mechanical properties.

This paper reveals that the hardness and the modulus of the bulk solder Cu/Sn–5Sb/Cu solder joints were improved with the addition of Cu, Ni and Ag trace elements. Meanwhile, the creep resistance and plasticity were also improved. This study has a great value for exploring high-performance Sn–Sb based solder alloy and has proved an example.