Effect of Arc Currents on the Mechanical, High Temperature Oxidation and Corrosion Properties of CrSiN Nanocomposite Coatings

In methods for multi-arc ion plating technology, the behavior and characteristics of the arc spot determine the physical characteristics of arc plasma and the properties of the subsequent deposited coatings. In this paper, the effect of arc currents on the hardness, friction coefficient, high temperature oxidation, and corrosion properties of the CrSiN coatings was studied. According to the XRD and SEM results, with the increase of arc currents, the coatings grew preferentially to the CrN (111) crystal direction, and the CrN (220) crystal phase appeared at high currents of 90 A. In addition, the number of large particles increased when the current exceeded 70 A. The HR-TEM results confirmed the formation of nanocomposite structure of nanocrystalline of CrN embedded into the amorphous phase of Si3N4 as explored by XRD. The maximum hardness was achieved at 3120 Hv when the coatings were deposited under currents around 70 A. However, the hardness values decreased with further increase of arc currents. From the contact of ceramic balls with the wear of coatings, the surface of coatings gradually produced friction marks, and the friction force increased from a steady friction force to a dynamic friction force. The high temperature oxidation results showed that fewer oxides were formed on the surface of the coatings when oxidized at 800 °C. It was also found that CrSiN nanocomposite coatings prepared at an arc current of 70 A had a larger corrosion potential and polarization impedance, which could effectively protect the tool matrix.

Improved Oxidation and Hot Corrosion Resistance of 1Cr11Ni2W2MoV Stainless Steel at 650 °C by a Novel Glass-Ceramic Coating

A novel glass-ceramic coating was applied onto the 1Cr11Ni2W2MoV stainless steel. The oxidation and corrosion behaviors of coated and uncoated steels were comparatively investigated in air and in the presence of NaCl + Na2SO4 eutectic deposits at 650 °C, respectively. Protective scales formed on the surface of stainless steel prevented the severe oxidation of the alloy. Catastrophic hot corrosion occurred on the steel when a salt film was attached, producing loose iron oxide layers and internal corrosion zone. The glass-ceramic coating acted as a barrier that effectively hindered the invasion of corrosive species during the oxidation and hot corrosion tests.

ATI X-751

ATI X-751 is a high-aluminum version of ATI X-750. It is a high-strength, precipitation hardenable, nickel-chromium alloy that employs nickel and titanium as the hardening elements. The alloy has good creep-rupture strength up to 815 °C (1500 °F), and excellent oxidation and corrosion resistance up to 980 °C (1800 °F). This datasheet provides information on composition, physical properties, and hardness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-776. Producer or source: ATI.

Investigation of the requirements for the selection of materials for high pressure Turbine blades of conventional turbojet engines

The material selection method is critically evaluated to enable high pressure (HP) turbine blades to deal with in-service damaging phenomena such as creep, low cycle fatigue and high cycle fatigue, oxidation and corrosion. The material selection method is analyzed in order to improve the service life of the aero engine. To increase the turbine inlet temperature, HP turbine blades need improved creep and fatigue resistance. more quality. By the typical working condition of HP turbine blade, using CES Edu Pack (CES) material selection software was used to select suitable materials for HP turbine blade material. Nickel based alloys are selected for HP turbine blades, such as Nickel-Cr-Co-Mo superalloy.

Magnesium containing High Entropy Alloys

High Entropy alloys (HEAs) or Complex Concentrated Alloys (CCAs) or Multi-Principal Element Alloys (MPEAs) is a matter of interest to material scientists for the last two decades due to the excellent mechanical properties, oxidation and corrosion resistant behaviors. One of the major drawbacks of HEAs is their high density. Mg containing HEAs show low density compared to peers, although extensive research is required in this field. This chapter aims to include all the available information on synthesis, design, microstructures and mechanical properties of Mg containing HEAs and to highlight the contemporary voids that are to be filled in near future.

Influence of Pre-Oxidation on High Temperature Oxidation and Corrosion Behavior of Ni-Based Aluminide Coating in Na2SO4 Salt at 1050°C

Aluminide coating is prepared on K438 Ni-based superalloy by pack cementation. The hot corrosion test of as-received and pre-oxidation aluminide coating in Na2SO4 salt are carried out at 1050°C. The coating morphologies, phase composition, and corrosion products are characterized by XRD, SEM, EDS, and TEM. The conclusion is that the pre-oxidation aluminide coating has excellent hot corrosion properties. After hot corrosion, the oxide scale of pre-oxidation aluminide coating is the thinnest and maintains good integrity. However, the oxide scale of as-received aluminide coating fluctuates greatly and there are corrosion cavities. CrS is formed in the alloy immediately below the oxide scale for the two coating systems.