This paper studied the effect of additives of 0.5–20 wt.% synthetic CaSiO₃ wollastonite on the thermodynamic, mechanical, and tribological characteristics and structure of polymer composite materials (PCM) based on ultra-high-molecular weight polyethylene (UHMWPE). Using thermogravimetric analysis, X-ray fluorescence, scanning electron microscope, and laser light diffraction methods, it was shown that autoclave synthesis in the multicomponent system CaSO₄·2H₂O–SiO₂·nH₂O–KOH–H₂O allows one to obtain neeindle-shaped nanosized CaSiO₃ particles. It was shown that synthetic wollastonite is an effective filler of UHMWPE, which can significantly increase the deformation-strength and tribological characteristics of PCM. The active participation of wollastonite in tribochemical reactions occurring during friction of PCM by infrared spectroscopy was detected: new peaks related to oxygen-containing functional groups (hydroxyl and carbonyl) appeared. The developed UHMWPE/CaSiO₃ materials have high wear resistance and can be used as triboengineering materials.

The application of titanium and its alloys under friction conditions is severely restricted, owing to their poor wear resistance. The paper presents the results of studies of the composition, microstructure, and tribological properties of Ti-TiC-based composite coatings formed on titanium alloys by the electroarc treatment in an aqueous electrolyte using a graphite anode. It has been found that TiC grains have a different stoichiometry and do not contain oxygen. The grain size varies from hundreds of nanometers to tens of micrometers, and the micro-hardness of the treated surface reached the value of 29.5 GPa. The wear resistance of the treated surface increased approximately 40-fold, and the friction coefficient with steel decreased to 0.08–0.3 depending on the friction conditions. The formation of a composite material based on Ti-TiC will contribute to the effective protection of titanium alloys from frictional loads in engineering.

The article considers the effect of a filler based on synthetic wollastonite (CaSiO₃), which is introduced into a polymer matrix made of ultra-high molecular weight polyethylene, on the tribotechnical parameters of the produced polymer composite material. Behavioral features of composites after friction were investigated by infrared spectroscopy and scanning electron microscopy. It was found that the introduction of wollastonite into the polymer matrix contributed to a reduction in the friction coefficient by 23% and the wear rate by four times. In the micrographs of the friction surfaces of the obtained composite, the formation of new secondary structures oriented along the friction direction, different from the initial polymer matrix, was revealed. The presence of wear products (oxidized polymer groups) and CaSiO₃ on the friction surfaces was recorded by infrared spectroscopy. It was established that the synthesized CaSiO₃ particles were deformed under the action of shear forces and participated in tribochemical processes.

Titanium-based alloys are widely used in aerospace engineering. They have good mechanical and corrosion properties but, in some cases, the material itself or the coating should meet some additional requirements. For example, it may be a requirement of high reflectance to provide effective temperature control. Wollastonite is a promising component for reflective coatings because it improves both their whiteness and mechanical properties. This paper presents the results of studying the composition, the structure and the adhesive strength of wollastonite-containing silicate coatings to titanium substrate. The surface of titanium samples was pre-treated by laser cladding with TiC and etching to provide surface porosity. It has been shown that such treatment allows a significantly increase in the adhesive strength of the coating to the substrate. A decrease in the adhesive strength was observed on titanium samples with an excess of TiO₂ on the surface. This is caused by the formation of crystalline PbTiO₃ at the interface.

It was shown that microwave treatment improves kinetics of formation and morphology of calcium hydrosilicates obtained from the waste of boric acid production, borogypsum.

The paper presents the results of a study of synthetic wollastonite from boric acid production waste (borogypsum) on the physical, mechanical and tribological properties of polymer composite materials based on polytetrafluoroethylene. Wollastonite was synthesized from borogypsum by its hydrothermal treatment in alkaline medium and subsequent calcination of the obtained precipitate at 900-1000 °C for 1 h. The product with a specific surface area of 1.4 m2/g and a density of 3.06 g/cm3 obtained under the above regimes is characterized by the presence of wollastonite of triclinic modification and the presence of CaSO4 anhydrite. The wollastonite particles are needle-shaped with a needle diameter of ~100 nm. Needle-shaped wollastonite particles are shown to be interconnected and form conglomerates and agglomerates ranging in size from 10 to 70 μm. Particle agglomerates are characterized by a wide unimodal distribution of pores with a maximum of 3.78 nm with conical and slit-like shapes. It was found that the use of wollastonite results in increased wear resistance of polymer composites based on PTFE. Composites filled with 10 and 20 wt.% of wollastonite are characterized by a 700-fold decrease in the rate of mass wear relative to the initial polymer. Physical and mechanical studies of PCM show that the introduction of wollastonite increases compressive strength and modulus of elasticity. However, a decrease in strain-strength parameters was observed. Scanning electron microscopy shows the formation of secondary structures on friction surfaces, which plays a role in the adaptation of the composite to wear. The method of IR spectroscopy of friction surfaces registered the appearance of new peaks corresponding to hydroxyl, carbonyl and carboxyl compounds. This indicates a certain contribution of wollastonite particles to tribochemical processes. For citation: Danilova S.N., Tarasova P.N., Yarusova S.B., Kapitonova Yu.V., Osipova V.N., Okhlopkova A.A., Gordienko P.S. Evaluation of the influence of wollastonite from technogenic waste on the properties of a polymer composite based on polytetrafluoroethylene. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 12. P. 102-112. DOI: 10.6060/ivkkt.20246712.7064.