Numerous industrial parts, devices, and processes are designed to withstand the conditions that lead to cavitation erosion. Metallic, ceramic, and composite materials used for these conditions must achieve specific mechanical characteristics required to resist cavitation erosion. When molten metal or alloy flows and comes into contact with refractory material or coated furnace linings, cavitation erosion can occur. This phenomenon is particularly expected in metallurgy, especially in casting operations. Alumina-based refractories, specifically low cement castable (ALCC), are often used in furnace lining applications due to their superior properties, such as high refractoriness, thermal stability, and mechanical characteristics. Mullite is another refractory material frequently used in foundry lining applications. It can be utilized as a coating in casting processes, such as the Lost Foam process, which is a novel method for producing high-quality, cost-effective castings. These two refractory materials were chosen to study their behavior under cavitation conditions. An ultrasonic vibratory test with a stationary specimen (ASTM G-32) was used for experimental cavitation determination. The results of mass loss and surface morphological parameters of degradation revealed that ALCC samples eroded predominantly at the surface, while the mullite samples exhibited more significant degradation by depth.

The choice of steel depends on environmental factors like temperature, pressure, and chemical exposure. Steel components in machinery often face varying conditions that can lead to damage, such as cavitation erosion. In this study, steel 42CrMo4 samples were chosen to represent a common and widely used steel. Application of this type of steel is often related to the statically and dynamically stressed components for vehicles, engines, and machines, where corrosion or cavitation can occur. The behavior of steel samples under conditions of cavitation erosion in distilled water was the focus of this paper. Testing was performed using a standard cavitation vibratory setup using a stationary specimen, according to the ASTM G-32 procedure. Image and morphological analyses were implemented to quantify the level of sample degradation caused by cavitation. The observed changes in the monitored parameters during testing are linked to the degradation mechanism of cavitation erosion. The results showed that pits began forming within 60 minutes, and afterward, the growth and merging of these pits significantly impacted the degradation process.

Engineering materials are often exposed to various extremely harsh surroundings such as high temperatures and/or pressure, thermal shocks, aggressive solutions, or cavitation erosion. The phenomenon of cavitation erosion might be expected in conditions of fluid-flowing where the parts of equipment include turbine blades, high-speed propellers, or pump parts. Such conditions usually cause surface degradation with defects in the form of pits and fractures, resulting in strength deterioration with a potential risk of failure, as well as a reduction in the materials' lifespan that requires additional expenses for failure analysis, repair, and/or replacement of parts. This paper will present the main results regarding the study on cavitation erosion resistance of two different engineering materials, austenitic stainless steel 316L and CuAlNi shape memory alloy (SMA). Cavitation erosion testing was carried out using an ultrasonic vibratory method with a stationary sample. The comparison of the behavior between these two materials in cavitation erosion conditions will be shown based on the results of mass loss and analysis of the pits formed over time. Using image analysis tools, the surface damage levels were quantified. Detailed analyses revealed that CuAlNi shape memory alloy (SMA) exhibited superior in terms of resistance and behavior compared to stainless steel.

Many steels are used in specific environments, while one of these is maritime applications. High-strength 42CrMo4 steel finds numerous applications in the marine industry, including shaft parts, crankshafts, connecting rods, drilling joints, pump parts, steam turbines, and salvage equipment. In order to provide performance reliability in the marine environment, it is essential to study the corrosion resistance of surfaces of 42CrMo4 steel components and parts. The steel's behavior is typically evaluated in a synthetic NaCl solution, which is prepared as a standard substitute for seawater. This paper is focused on the behavior of the steel samples under corrosion conditions in NaCl solution. The level of sample surface degradation which is caused by the corrosion over a 4-month exposure period was evaluated using SEM/EDS analysis. The mass loss increased during the testing period, following an almost linear model in all time periods.

Numerous industrial equipment are designed to withstand harsh operating conditions that among others include cavitation erosion. This study examined the cavitation erosion behavior of mullite, a common material used in furnace linings and casting processes such as Lost Foam which is a novel way to produce castings offering both high quality and reasonably priced. The ultrasonic vibratory method with a stationary sample was employed to achieve cavitation erosion, while image analysis was used to measure the degree of surface deterioration. This study aimed to assess the lifetime of mullite under cavitation exposure by quantifying the morphological parameters of the defects through image analysis and by monitoring material behavior. The obtained results were discussed and analyzed in order to understand degradation mechanisms and sample resistance to cavitation erosion. The results demonstrate that mullite is highly resistant to cavitation, as the volume loss is minimal and the surface degradation is below 6% after 180 minutes of exposure.

Since depletion of natural resources and the amount of construction and demolition waste have overcome the socially and environmentally acceptable level, the construction industry must address this issue and reduce its impact on the environment. A step towards sustainability in the construction industry is the application of recycled aggregates and supplementary cementitious materials as integral components of concretes, which provides conserving natural aggregates and waste reduction. This study adopts a holistic approach to producing green self-compacting concrete with the highest portion of recycled aggregate as a replacement for natural aggregate and fly ash as filler. Based on the particle packing density method, four series of self-compacting concrete were prepared: the first series was made with natural fine and coarse aggregate, the second series was made with fine natural aggregate and recycled coarse aggregate, the third with 50 % (by mass) of fine natural aggregate replaced by recycled fine aggregate and recycled coarse aggregate, and the fourth series completely with recycled fine and coarse aggregate. The content of fly ash remained constant. Regardless of the expected decrease of workability in a fresh state with the increase of the recycled aggregate content, all series exceeded the requirements set for the hardened structural concrete.

Concrete is a material that has been used for centuries and is often modified using polymers. In the last fifty years, synthetic polymers have been used for the modification of concrete, but also for the production of concrete. In recent decades, sulfur concrete has been an interesting product that can be used mainly in low-rise construction due to its characteristics. In this work, we used the starting mixture for the preparation of sulfur concrete (sand, elemental sulfur with the addition of modified sulfur and fillers) heated to a temperature of 120 ºC to 170 ºC and homogenized. The results of previous research on the production of sulfur concrete showed that the density of the obtained product changes depending on the type as well as the amount of filler added to the basic mixture based on raw materials. Talc, microsilicon, plate alumina and fly ash were used as fillers. The amounts of fillers were 0%, 1%, 3%, 5%, 7% and 10%.

The paper presents the results of the research cavitation erosion behavior of samples based on talc with addition of domestic zeolite from the Zlatokop deposit. Samples based on talc with 15 % of zeolite, from Zlatokop (Vranjska Banja), sintered at 1200ºC were used in this investigation. Resistance to cavitation was monitored by the ultrasonic vibratory cavitation set up with a stationary specimen and measuring respectively determining the specimens' mass loss. Image analysis and Young's modulus of elasticity were used to determine the level of degradation of the sample surface and sample's volume. Obtained results showed good resistance of the refractory samples based on talc and zeolite to the cavitation erosion, which indicates the possibility of application ceramic samples based on talc and zeolite in various areas of industry where the presence of destruction due to the effect of cavitation is expected.

Thermal shock stability plays a great role in the selection of optimal refractory material. Different methods of characterization were developed for this purpose, including the implementation of nondestructive testing. Image analysis is a very well method for characterization of different materials structures, as well as changes and occurred defects in structure caused by different influences. In this paper, possible application of image analysis will be presented related to the monitoring thermal shock behavior of selected refractory materials. Different parameters such are R parameter, level of destruction, as well as determination of morphological descriptors (area, perimeter, diameter, roundness) using Image analysis, will be presented.