Search Results for water vapor

This article discusses the influence of water vapor on the performance of YSZ thermal barrier coatings, particularly the oxidation resistance of the bond coat.

Understanding detrimental alpha case formation during heat treatment of titanium parts is increasingly important as titanium use in aerospace and medical applications continues to grow.

Residual gas analysis shows that vacuum furnaces with graphite hot zones are more economical than all-metal designs and are capable of producing contamination-free surfaces.

Successful part brazing relies on proper joint design, part cleanliness, and correct fixturing of part assemblies. Routine furnace maintenance allows repeatable, quality brazing results over time. This article describes aluminum brazing processes and process control considerations.

Early consideration of scale-up requirements can help circumvent downstream problems when implementing thermal processes for the production of new materials and product forms. Examples are given showing how success is achieved when scaling opportunities and challenges are identified early in the development process.

Alloy developers worldwide have struggled to create creep-resistant alumina-forming, iron-based austenitic stainless steels for use as high-temperature structural alloys, but with limited success in balancing alloy cost, oxidation, and creep resistance. This article describes the research and development of a novel cast alumina-forming austenitic stainless steel. This work won the prestigious Engineering Materials Achievement Award presented at IMAT 2023 in Detroit.

This article considers the effect of atomic oxygen exposure in low earth orbit on thin film solid lubricants of molybdenum disulphide and diamond-like carbon nanocomposites, a silica-containing diamond-like carbon film. Advances in deposition methods over the past few decades enable dense films to be created that are more resistant to oxidative degradation and the effects of adsorbed moisture than their predecessors. Further, incorporating additional phases improves the tribological performance of the films in a range of atmospheres.

Accurate and continuous dew point measurement is key to maintaining the atmosphere required to achieve high quality and consistency of sintered products in powder metallurgy processing.

A novel hot zone design featuring new graphite boards reduces heat loss and improves overall hot zone power requirements.

Aircraft engines that minimize fuel consumption and operate on sustainable aviation fuels are key to meeting the air transportation sector’s commitment to net zero CO 2 emissions by 2050. This article reports on work to implement sustainable propulsion technologies, including advanced gas turbine propulsion technologies, engines that are compatible with approved sustainable aviation fuels, hybrid-electric propulsion, and hydrogen propulsion. The article also describes efforts to reduce the environmental footprint related to condensation trails (contrails) from aircraft engine exhaust plumes.

Processes such as combustion, calcination, thermal cracking, and gasification are typically carried out in industrial plants featuring kilns, rotary kilns, or drying ovens. The dynamic, high-temperature process of horizontal contact drying makes it possible to treat bulk materials more efficiently and evenly than traditional drying ovens and rotary kilns.

This article discusses some of the newer thermal barrier coating materials being considered for use in gasified coal-based turbines and how they compare with conventional materials in terms of bond coat oxidation and topcoat damage due to particle erosion and molten ash deposits.

Induction coils are considered the weakest link in an induction hardening system, so advanced designs and precise fabrication are paramount to ensure long life while producing high quality treated parts. This article describes material selection and fabrication techniques for conventional inductors and new breakthrough designs.

Using virtual tools to study aluminum cylinder head quenching processes delivers valuable information for process design and optimization. In this study, cooling curves and temperature gradients generated by air and water quench modeling methods were used to evaluate quenching performance for various quenching configurations.

A look at how the high energy breaks, conductive debris, and ergonomic issues unique to composites testing can be resolved with proper equipment set up.

Moisture-electric energy transformation (MEET) technology is being developed to further expand the utilization of environmental energy sources like thermal power, wind power, hydropower, and solar energy. The goal of the MEET technology is to extract power from environmental moisture with as few conversion processes as possible to satisfy the ever-growing demand for new and more portable energy sources The use of cold spray to produce MEET devices results in a greener process. While the suitability of polyether ether ketone as a MEET material was proven and the deposition of PEEK using cold gas dynamic spray (CGDS) was achieved, additional work is needed to fully characterize the manufacturing of PEEK-based MEET devices via CGDS.

Terahertz time-domain spectroscopy is a powerful and nondestructive analytical characterization technique for investigating ceramics, glasses, and composites.

Stress corrosion cracking is an insidious form of damage that can occur when a susceptible metal is subjected to a tensile stress in a specific environment. To relieve tensile stresses at welded joints, postweld heat treatment can be helpful in reducing the susceptibility of carbon steel fabrications to SCC. When planning to use stainless steels in chloride-containing environments, it is advisable to select alloys that have been specifically developed to resist stress chloride cracking such as ferritic-austenitic (duplex) alloys, low-carbon ferritic alloys, and 6% Mo austenitic alloys or to select high-nickel alloys.

Thin film cathodic arc PVD coatings offer an easy and economical way to optimize surface properties without changing bulk performance. This article describes a modified cathodic arc process called arc plasma acceleration (APA), which enables production of high density, thin film coatings containing minimal macroparticles.

This article explains why defining gas quenching in terms of bar pressure no longer applies and how a new definition based on heat transfer and cooling rate leads to a better understanding of which steels and what cross-sections can be hardened via gas quenching.