Abstract This review aims to present a critical overview of indium tin oxide (ITO) thin film preparation methods, structure–property relationship, and its humidity sensing. A range of passive and active humidity sensors with thin films (based on metal oxides) detects humidity. ITO thin film has advantageous properties, such as low resistivity and high stability, making it highly suitable for humidity sensing applications. ITO thin film has shown the efficient level of humidity sensing, and a compatible size of humidity sensor can monitor the interface conditions humidity. So far, the application of ITO thin film for humidity measurement has yet to be explored at commercial scale, specifically in the detection of lower environmental humidity range (below 5% relative humidity (RH)). The research reveals a gap in improving the ITO thin film properties with an optimal range of preparation conditions. The research opportunities in the preparation, properties, characteristics, and efficient humidity sensitivity of ITO thin film are reviewed in this work.
In response to environmental concerns, there is a growing demand for durable and sustainable mechanical seals, particularly in high-risk industries like chemical, petroleum, and nuclear sectors. This work proposes augmenting the durability and sustainability of silicon carbide (SiC) ceramic seals with the application of a nanodiamond composite (NDC) film through coaxial arc plasma deposition (CAPD) in a vacuum atmosphere. The NDC coating, with a smooth surface roughness of Ra = 60 nm as substrate, demonstrated a thickness of 1.1 μm at a deposition rate of 2.6 μm/hr. NDC film has demonstrated exceptional mechanical and tribological characteristics, such as a hardness of 48.5 GPa, Young's modulus of 496.7 GPa, plasticity index (H/E) of 0.098, and fracture toughness of H3/E2 = 0.46 GPa, respectively. These NDC films showcased commendable adhesion strength (> 60 N), negligible wear, and low friction (≤ 0.18) during dry sliding against a SiC counter material. Raman analysis has confirmed the nanocomposite structure of NDC film, emphasizing the role of highly energetic carbon ions in enhancing film adhesion by forming SiC intermetallic compounds at the interface through the diffusion of silicon atoms from the substrate into the films. The abundance of grain boundaries and rehybridization of carbon sp3 to sp2 bonding is perceived to improve tribological performance. CAPD excels in synthesizing long-life eco-friendly NDC coatings for durable and sustainable mechanical seals, featuring smooth surfaces, superior adhesion, outstanding hardness, and wear resistance, making them high potential candidates for various tribological applications.
Abstract This chapter provides an overview of the common types of defects found in various structural materials and joints in aircraft. Materials manufacturing methods (including large-scale production) have been established in the aircraft industry. However, as will be seen in this chapter, manufacturing defects and defects during in-service conditions are very common across all material types. The structural material types include metals, composites, coatings, adhesively bonded and stir-welded joints. This chapter describes the defect types as a baseline for the description of their detection with the methods of Chap. 10.1007/978-3-030-72192-3_5 to 10.1007/978-3-030-72192-3_8 . Based on the understanding of the defect types, there is great expectation for a technical breakthrough for the application of structural health monitoring (SHM) damage detection systems, where continuous monitoring and assessment with high throughput and yield will produce the desired structural integrity.
Desalination is an energy intensive process requiring adequate pre- and post- treatment. The novelty of this paper is that it jointly reviews the technologies for pre-treatment, desalination and post-treatment and bridges the gap between them while comparing the treatment methods needed depending on the type of feed water including seawater, brackish water, municipal and industrial wastewater. Those different streams show wide variability, sometimes containing organics, oil or scaling precursors which require adequate treatment. Nowadays, membrane pre-treatment methods have become promising alternatives to conventional pre-treatment techniques thanks to their flexibility. Hybrid desalination technologies have shown great potential in reducing energy consumption. Moreover, desalination plants produce large quantities of brines which require post-treatment to reduce environmental impacts. Current research on post-treatment is looking into recovering salts, metals and potable water from brines to achieve zero liquid discharge (ZLD). Thermal-based ZLD technologies are capable of extracting those resources while membrane-based ZLD methods are mostly limited to pre-concentration and water recovery due to fouling issues. Several studies have shown that ZLD systems can lower the cost of water and increase profitability if crystals and water are recovered and sold for additional revenue.
The aim of the present investigation is to understand the localised failure mechanism of diamond-like carbon (DLC) film during multiple load cycle nanoindentation. The DLC film investigated was 500 nm thick sputter coated on Si (100) wafer of 500 μm thickness. Multiple load cycle nanoindentation tests under diamond Berkovich and conical indenters were performed using a calibrated NanoTest at five different load ranges between 0·1 and 500 mN. Test results indicated forward deviation, no deviation and backward deviation of the force–displacement profile, which provided some insights to the mechanisms of localised film failure. During backward deviation, film failure starts from interfacial delamination. This was observed for a conical indenter in a particular load range (1–10 mN). An elastic finite element model during nanoindentation loading indicated that this was caused by the location of maximum stress near the interface. Forward depth deviation was observed for conical and Berkovich indenter at all the other load ranges.
During thermal spray coating, residual strain (or stress) is formed within the coating and substrates due to many processes (quenching stress, peening effect, deposition temperature, lamella structure) and micro-structural phase changes. It is also known that the residual stress values of thermally sprayed coatings are dependent upon the measurement method. Neutron diffraction technique can provide a non-destructive through-thickness residual strain analysis in thermally sprayed components with a level of detail not normally achievable by other techniques. Despite this advantage, the number of studies involving neutron diffraction analysis in thermal spray coatings remain limited, partly due to the limited number of neutron diffraction strain measurement facilities globally, and partly due to the difficulty is applying neutron diffraction analysis to measure residual strain in the complex thermal spray coating micro-structure. This paper provides a comprehensive guide to researchers planning to use this technique for thermal spray coatings, and reviews some of these studies. ENGIN-X at the ISIS spallation source in the UK is a neutron diffractometer (time-of-flight) dedicated to materials science and engineering with high resolution and versatile capabilities. The focus is on the procedure of using ENGIN-X diffractometer for thermal spray coatings with a view that it can potentially be translated to other neutron diffractometers. Neutron sources worldwide (e.g. Africa, Asia, Australia, Europe, and North America) have been used to measure strains in various materials, and here, we present few examples where thermal spray coatings have been characterized at various neutron sources worldwide, to study the residual strains and micro-structures.
The geological storage of CO2, also referred to as CO2 geosequestration, represents one of the most promising options for reducing greenhouse gases in the atmosphere. However, most of the time, CO2 is captured and compressed together with small amounts of other industrial gases such as SO2 and H2S, incurring extra costs to separate these other acid gases before CO2 storage in depleted petroleum reservoirs or aquifers. Moreover, during CO2 geosequestration in reservoirs, pressure variations during injection could force some amount of CO2 into the caprock, through diffusion or if the capillary entry pressure of the caprock is exceeded; thereby, altering the petrophysical, geochemical, and geomechanical properties of the caprock. Therefore, studies on the co-injection of CO2 with other acid gases from industrial emissions and their impact on reservoir and cap rocks integrity are paramount. In this study, numerical simulations were performed using TOUGHREACT codes, to investigate the co-injection of SO2 and H2S (separately) with CO2 in carbonate and sandstone formations, and their migration to shale caprock. Furthermore, mathematical models were developed to evaluate the mineralogical brittleness index (a measure of integrity) of the rocks, and validated with experimental data. The findings of the study revealed that during CO2 geosequestration, the brittleness of shale and sandstone rocks decreases, while the change in the brittleness of the carbonate rocks varies depending on calcite precipitation or dissolution. The co-injection of H2S or SO2 with CO2 does not increase the brittleness of shale caprocks, as the brittleness is impacted mainly by the CO2 gas.
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