Browse Topic: Ceramics
Many performance sport passenger vehicles use drilled or grooved cast iron brake rotors for a better braking performance or a cosmetic reason. Such brake rotors would unfortunately cause more brake dust emission, appearing with dirty wheel rims. To better understand the effects of such brake rotors on particle emission, a pin-on-disc tribometer with two particle emission measurement devices was used to monitor and collect the emitted airborne particles. The first device was an aerodynamic particle sizer, which is capable of measuring particles ranging from 0.5 to 20 μm. The second device was a condensation particle counter, which measures and collects particles from 4 nm to 3 μm. The testing samples were scaled-down brake discs (100 mm in diameter) against low-metallic brake pads. Two machined surface conditions (plain and grooved) with uncoated or ceramic-coated friction surfaces were selected for the investigation. The results showed that the grooved friction surface led to a higher
The phenomenon of drop-wall interaction plays a crucial role in a wide range of industrial applications. When liquid droplets come into contact with a high-temperature surface, it can lead to thermal shock due to rapid temperature fluctuations. This abrupt temperature change can generate thermal stress within the solid wall material. If the thermal stress exceeds the material's strength in that specific stress mode, it can result in material failure. Therefore, it is imperative to delve into the evolving temperature patterns on high-temperature surfaces to optimize material durability. This study focuses on investigating drop-wall interactions within the context of engine environments. To achieve this, the Smoothed Particle Hydrodynamics (SPH) method is employed to simulate the impact of fuel droplets on a silicon nitride wall. The goal is to understand the heat transfer mechanisms, thermal penetration depths, and temperature distributions within the heated wall. Furthermore, this
Additive manufacturing enables unrivaled design freedom and flexible fabrication of components from a wide range of materials including metals, composites, polymers, and ceramics. The near net shape parts are made by processes like sequential melting or layer-by-layer material deposition with a complex set of processing variables. The sequential nature of the process means that every step can impact the next and thus, tools to evaluate that risk before and during manufacturing are necessary
In this study, we have investigated the microstructural characteristics, the mechanical properties, and the dry sliding wear behavior of a ceramic coating consisting of zirconia (ZrO2) and alumina (Al2O3) deposited by flame spraying. A series of wear tests were carried out under a variety of loads and at two different sliding speeds. The evaluation included an examination of the coating microstructure, microhardness, coefficient of friction (COF), and wear resistance of the flame-sprayed coating. The results showed that the coatings had a perfectly structured micro-architecture and were metallurgically bonded to the substrate. The Al2O3 coating exhibited a fine granular structure with pores and oxides. The microstructure of Al2O3-10 wt.% ZrO2, on the other hand, showed a blocky structure with a uniform distribution of ZrO2 inclusions in the composite coating. X-ray diffraction (XDR) results showed that the phases in both coatings were predominantly α-Al2O3 with a minor presence of γ
Billions of people around the world lack access to clean, drinkable water. A research team led by engineers at The University of Texas at Austin has developed a new water filtration system using locally sourced materials for members of the Navajo Nation in the Southwest
This specification covers characteristics for chemistry, microstructure, density, hardness, size, shape, and appearance of zirconium oxide-based ceramic shot, suitable for peening surfaces of parts by impingement
Many of today’s high-performance technologies — nuclear reactors, spacecraft, concentrated solar plants, and hydrogen cells — require advanced materials. Advanced means they are made of metals and ceramics that can withstand extreme conditions or meet exacting specifications
Photonics, the science and technology of light, relies on optical components that affect light transmission in very specialized ways. To achieve the precision required, the optical components must be precisely ground from standard forms of glass, ceramics, or other materials to exceedingly tight tolerances, in many cases with extreme levels of flatness and parallelism
The impetus for advancing brittle ceramic materials used for armor applications has been identified as both an increased mass efficiency for greater weight reduction and enhanced performance against ballistic threats through manipulating the physics of failure
This research developed and utilized advanced processing, modeling, and micromechanical tools to discover and demonstrate hierarchically structured diamond-based composites with exceptional mechanical and ballistic behavior. Understanding how nanoscale and mesoscale microstructural features in diamond–silicon carbide (SiC) composites influenced the physics of failure was critical in uncovering ways to improve performance for soldier protection and discover potential defeat mechanisms
This specification covers general requirements for the apparatus, material, and procedures to be used in the processing of magnesium base alloys for the purpose of increasing their corrosion resistance and by producing surfaces suitable for organic paint finish systems
This specification covers a corrosion- and heat-resistant cobalt alloy in the form of sheet, strip, and plate
This recommended practice describes the materials, related equipment, and particular processing techniques utilized in process science curing of composite hardware where pressure is imparted specifically to the resin of curing composites. Included as Appendix "A" to this ARP is a discussion of the particular techniques developed for a processing science philosophy which has consistently produced void and porosity-free, large area, thick composite structures
Composite materials have time and again proven to be highly useful, especially in the aerospace industry with the increasing need for light-weight materials albeit with high stiffness to strength ratios. The Ceramic Particle Reinforced Composites can be effectively utilized in tuning the natural frequencies of components by varying the volume fractions up to 40% with the help of Representative Volume Element (RVE) / Unit Cell Models as explained in Reference [1]. The aim of this paper is to tune the natural frequencies of a typical blade used in a gas turbine engine by modifying the material properties without changing the design profile significantly. The design profiles of blades are arrived at after a lot of engineering iterations from aerodynamics stability point of view and are also finalized based on meeting key performance parameters. However, the structural analysis studies are carried out after the profile generation, which may sometime predict that the natural frequencies are
Scientists have developed a ceramic-based ink made of calcium phosphate to 3D print bone parts complete with living cells that could be used to repair damaged bone tissue. The 3D printer method is ceramic omnidirectional bioprinting in cell-suspensions (COBICS), which enables surgeons to print bonelike structures that harden in a matter of minutes when placed in water. The material can be created at room temperature — complete with living cells — and without harsh chemicals or radiation
In sheet metal testing, in-situ crack detection is either performed manually by purely visual inspection by the machine operator or automatically by a crack detection system. The automatic crack detection method, commonly integrated in sheet metal testing machines, evaluates the drawing force during forming. However, friction, vibration, and machine noise prevent reliable crack detection in thin sheets and foils. The same disturbance variables also prevent robust crack identification in thin sheets and foils by systems that analyze structure-borne sound. Crack detection systems that use reflected light methods, on the other hand, necessitate homogeneous illumination and are interfered by highly reflective as well as inhomogeneous sheet surfaces. In order to avoid the above-mentioned disadvantages of the currently existing crack detection methods, a procedure based on transmission-illumination was developed. Fundamental to this new development is the use of a translucent punch, which
In recent years, bearing electrical failures have been a significant concern in electric cars, restricting electric engine life. This work aims to introduce a coating approach for preventing electrical erosion on 52100 alloy steel samples, the most common material used on manufacturing bearings. This paper discusses the causes of shaft voltage and bearing currents, and summarizes standard electrical bearing failure mechanisms, such as morphological damages and lubrication failures. Alumina coatings are suitable for insulating the 52100 alloy steel samples because alumina coatings provide excellent insulation, hardness, and corrosion resistance, among other characteristics. The common method to coat an insulated alumina coating on the bearing is thermal spraying, but overspray can cause environmental issues, and the coating procedures are costly and time-consuming. Based on the research, this article briefly discusses employing plasma electrolytic aluminating to coat 52100 alloy steel
We demonstrate a virtual proof-of-concept design and experiment for energy harvesting enabling economic and environment-friendly aircraft by recycling forces for power conversion. The harvesting uses piezoelectric materials for extracting energy from the impact at the touchdown during the landing of an aircraft and direct current (DC) generators powered by the rotational motion of the aircraft wheels during taxiing. The design begins with a multidomain model comprising multibody dynamics, mathematical descriptions, abstract behavioral blocks, and programmed code. Piezoelectric harvesting explores six types of materials consisting of ring and disk pad geometries. Both geometries are typical configurations in suspension systems. Recent advances have shown the potential of getting higher voltage out of new materials properties. Our objective is to determine the useful impact force during a touchdown on the pads and a pad type that maximizes the power transfer. The evaluation shows that
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