MAX phase materials a new family of ternary layered carbide and nitride compounds are represented by the general formula of M_n+1AX_n, where n = 1 ∼ 3, M stands for early transition metal, A express A-group elements, and X is either nitrogen or carbon. As early as 1960s, this materials had been paied much attention due to their unique physical properties combination of metals and ceramics such as machinability, low hardness, excellent electrical, good thermal conductivity, damage tolerance, thermal shock resistance, high elastic moduli, oxidation and corrosion resistance. Therefore, MAX phase ceramics can be used as structural and functional materials, and is regarded as an ideal strengthening phase for metal matrix composites. Researchers have recognized the potentially technologically important application of this emerging material in the fields of aerospace, high-speed rail, nuclear industry, gas igniter, heat exchanger, high thrust rocket nozzle, electric brush, kiln furniture, metal refining electrode and high-temperature seal. In recent years, a new research caused heightened concerns on MAX phase, as the feasibility of attaining MXenes via selectively etching these and removing of the A-group element. In this review, the development of MAX phase and th e characteristics and applications of its derivative of MXenes are introduced in the first place. Next, the structure, morphology, electronic structure and diversity of the MAX phase are described. Thirdly, the different preparation methods and related applications of MAX phase films, bulk materials and powder materials are systematically introduced according to the current preparation technologies. Finally, the future development potential of MAX phase and the related improvement of the research subject are prospected. It aims to provide theoretical guidance and new ideas for synthesizing and creating new and excellent MAX phase materials, so that this new type of material can be put into social production and application in large quantities.

Surface texture (ST) has been confirmed as an effective and economical surface treatment technique that can be applied to a great range of materials and presents growing interests in various engineering fields. Ti6Al4V which is the most frequently and successfully used titanium alloy has long been restricted in tribological-related operations due to the shortcomings of low surface hardness, high friction coefficient, and poor abrasive wear resistance. Ti6Al4V has benefited from surface texture-based surface treatments over the last decade. This review begins with a brief introduction, analysis approaches, and processing methods of surface texture. The specific applications of the surface texture-based surface treatments for improving surface performance of Ti6Al4V are thoroughly reviewed from the point of view of tribology and biology.

Because of its disadvantages of low surface hardness values, a high coefficient of friction and poor wear resistance, Ti6Al4V alloy is seldom used in tribological-related engineering components. To improve the surface performance of Ti6Al4V alloy used as petroleum tubes for oil and gas exploitation applications, a thermal oxidation (TO) process was applied to fabricate a TO layer on the Ti6Al4V substrate at 700 °C for 30 h. A microstructural characterization of the produced TO layer was systematically performed. Comparative estimations of the electrochemical corrosion, erosive-wear and corrosive-wear behaviors on the TO layers and Ti6Al4V alloys were conducted in CO₂-saturated simulated oilfield brine. The results showed that the obtained TO layer was mainly composed of rutile phase TiO₂ and minor anatase phase TiO₂. The continuous and compact TO layer reached a total thickness of about 20 μm. The TO layer contained an external oxide-layer and an internal O-diffusion layer. The concentration of O had a gradient descent along the thickness of the TO layer. The TO layer showed enhanced hardness and good bonding strength. Compared to the Ti6Al4V alloy substrates, the TO layers revealed superior surface performance in the electrochemical corrosion, erosive-wear and corrosive-wear tests. Excellent chemical stability, mechanical isolation action, high hardness and bonding strength contributed to the promising surface performance of the TO layer. TO treatment makes it possible to create a working surface on the Ti6Al4V alloy with enhanced surface hardness and wear resistance.

Surface texturing-plasma nitriding duplex treatment was conducted on AISI 316 stainless steel to improve its tribological performance. Tribological behaviors of ground 316 substrates, plasma-nitrided 316 (PN-316), surface-textured 316 (ST-316), and duplex-treated 316 (DT-316) in air and under grease lubrication were investigated using a pin-on-disc rotary tribometer against counterparts of high carbon chromium bearing steel GCr15 and silicon nitride Si₃N₄ balls. The variations in friction coefficient, mass loss, and worn trace morphology of the tested samples were systemically investigated and analyzed. The results showed that a textured surface was formed on 316 after electrochemical processing in a 15 wt % NaCl solution. Grooves and dimples were found on the textured surface. As plasma nitriding was conducted on a 316 substrate and ST-316, continuous and uniform nitriding layers were successfully fabricated on the surfaces of the 316 substrate and ST-316. Both of the obtained nitriding layers presented thickness values of more than 30 μm. The nitriding layers were composed of iron nitrides and chromium nitride. The 316 substrate and ST-316 received improved surface hardness after plasma nitriding. When the tribological tests were carried out under dry sliding and grease lubrication conditions, the tested samples showed different tribological behaviors. As expected, the DT-316 samples revealed the most promising tribological properties, reflected by the lowest mass loss and worn morphologies. The DT-316 received the slightest damage, and its excellent tribological performance was attributed to the following aspects: firstly, the nitriding layer had high surface hardness; secondly, the surface texture was able to capture wear debris, store up grease, and then provide continuous lubrication.