Materials degradation refers to the process by which materials lose their properties and functionality over time due to various environmental, mechanical, or chemical factors. This deterioration can affect the material's strength, appearance, and performance, making it less suitable for its intended application. There are several types of materials degradation, including: 1. **Chemical Degradation**: This involves reactions with environmental agents, such as oxidation, hydrolysis, or corrosion, that may alter the chemical composition of the material.
Corrosion is a natural process that involves the deterioration of materials, typically metals, as a result of chemical reactions with their environment. This process often leads to the formation of oxides, hydroxides, or other compounds, which can weaken a material's structure and integrity. Corrosion can be caused by factors such as moisture, oxygen, acids, salts, and other environmental agents.
475 °C embrittlement refers to a phenomenon observed in certain types of ferritic stainless steels and other iron-based alloys, where prolonged exposure to temperatures around 475 °C (about 885 °F) leads to a reduction in ductility and toughness. This embrittlement is primarily attributed to the precipitation of an iron-rich phase known as "sigma phase" or the formation of non-uniform compositions in the microstructure, which can lead to the loss of the material's structural integrity.
Ablation generally refers to the process of removing or destroying tissue or material through various methods. The term is used in several contexts, each with its own specific meaning: 1. **Medical Context**: In medicine, ablation refers to the removal of tissue, often using techniques such as surgery, laser treatment, radiofrequency, or cryotherapy. For example, cardiac ablation is a procedure used to treat arrhythmias by destroying small areas of heart tissue that cause abnormal electrical signals.
Abrasion is a mechanical process that involves the wearing away or removal of material from the surface of an object due to friction, rubbing, or erosion caused by contact with another surface or particles. This process can occur naturally, through environmental factors such as wind, water, or ice, or it can be induced artificially, such as in manufacturing or construction contexts. In the context of geology, abrasion is a key mechanism of erosion, where rock and soil particles are worn down by the action of transported materials.
Agents of deterioration refer to the various factors and conditions that can cause the degradation, damage, or decline of objects, materials, or collections, particularly in the context of cultural heritage, libraries, museums, and archival storage. Understanding these agents is essential for the preservation of artifacts, documents, and other items of historical and cultural significance.
Coble creep refers to a specific mechanism of creep deformation that occurs in materials, particularly ceramics and polycrystalline materials, at elevated temperatures. It is named after the materials scientist R. L. Coble, who characterized this mode of creep in the context of grain boundary sliding in polycrystalline materials. The mechanism of Coble creep involves the movement of atoms along grain boundaries. This is typically observed in materials with a fine-grained microstructure at temperatures close to their melting point.
Compact disc bronzing is a phenomenon that occurs in some optical discs, particularly CDs, where they develop a bronze or gold tint on their surface. This discoloration is often a sign of deterioration due to oxidation or degradation of the disc materials, specifically the reflective layer. The bronzing effect may be caused by several factors, including: 1. **Material degradation**: The dye used in the recording layer of the CD can degrade over time, especially when exposed to moisture, heat, or light.
Conchoidal fracture is a type of breakage that occurs in certain materials, most notably in glass, quartz, and some other minerals. It is characterized by smooth, curved surfaces that resemble the shape of a shell or the curves of a conch. This type of fracture does not follow any predetermined planes of weakness (such as cleavage or grain boundaries) and instead propagates in a way that creates sharp, glassy edges.
"Concrete cancer" is a colloquial term that refers to the deterioration of concrete structures, primarily caused by the corrosion of reinforcing steel (rebar) embedded within the concrete. This phenomenon typically occurs when moisture, salts, and other corrosive agents penetrate the concrete, leading to the rusting of the rebar. As the steel rusts, it expands, causing the surrounding concrete to crack and spall, which can compromise the structural integrity of the element.
Concrete degradation refers to the deterioration of concrete structures or materials over time due to various environmental, chemical, physical, and mechanical factors. This process can lead to a reduction in the strength, durability, and overall performance of concrete, compromising its integrity and potentially leading to structural failures.
Crevice corrosion is a localized form of corrosion that occurs in the stagnant microenvironments created in crevices or tight spaces. It is typically found in areas where two materials are in contact, such as under gaskets, washers, or any part where there is a gap that can trap corrosive agents, such as water or ionic solutions. The primary mechanism behind crevice corrosion involves the differential concentration of ions within the crevice compared to the external environment.
Cultural heritage at risk from climate change refers to the threats that climate-related impacts pose to sites, structures, traditions, and practices that hold historical, cultural, or artistic significance. This risk can manifest in various ways: 1. **Physical Damage to Sites**: Extreme weather events, rising sea levels, and increased temperatures can lead to the deterioration of buildings, monuments, archaeological sites, and landscapes.
Damage mechanics is a field within materials science and engineering that studies the initiation and propagation of damage in materials under various loading conditions. It encompasses the understanding of how materials respond to external forces, how microstructural defects evolve, and the mechanisms that lead to failure. The key components of damage mechanics include: 1. **Types of Damage**: Damage can be classified into several types, including: - Microstructural damage (e.g.
Diffusion creep is a mechanism of deformation that occurs in materials, particularly in solids under high temperature and stress conditions. It is characterized by the movement of atoms or vacancies within the crystal lattice of a material, allowing it to deform without the need for dislocation movement, which is a more conventional mechanism of plastic deformation. The process occurs through the diffusion of atoms in the lattice, which can happen via two main types: grain boundary diffusion and lattice diffusion.
Disc rot refers to the deterioration of optical discs, such as CDs, DVDs, and Blu-ray discs, due to various factors that cause physical and chemical degradation over time. This process can lead to data loss, as the affected areas become unreadable by laser-disc players or computers. Common causes of disc rot include: 1. **Physical Damage**: Scratches, cracks, or other physical defects can lead to disk malfunction.
Embedment generally refers to the act of embedding something within another material or system. The term can have different meanings based on the context in which it is used: 1. **Information Technology**: In IT, embedment often relates to the incorporation of resources such as videos, images, or interactive content directly into a web page or application. For example, embedding a YouTube video in a blog post allows the video to be viewed directly without navigating to YouTube.
Embrittlement is a process that reduces the ductility of a material, making it more brittle and prone to fracture under stress. This phenomenon can occur in various materials, particularly metals and alloys, and can significantly impact their mechanical properties and performance. There are several types of embrittlement, including: 1. **Hydrogen Embrittlement**: Involves the diffusion of hydrogen into metals, which can lead to the formation of microscopic cracks and ultimately failure, particularly in high-strength steels.
Forensic polymer engineering is a specialized field that combines principles of polymer science, materials science, and forensic investigation to analyze and interpret the properties and behaviors of polymer materials in legal or investigative contexts. This discipline is often employed in cases involving polymer products, such as plastics, composites, and elastomers, particularly when failure, damage, or degradation occurs.
Foxing refers to the yellowish-brown spots or discoloration that can appear on paper, particularly in books, due to age, humidity, and exposure to light. This phenomenon is often caused by the breakdown of the paper's fibers, mold, or chemical reactions involving impurities in the paper or ink. Foxing is commonly seen in older books, particularly those that are not stored properly. Collectors often seek to minimize or remove foxing to preserve the integrity and aesthetic of the printed work.
Fretting refers to a form of wear and degradation that occurs at the interface of materials that are in close contact, typically under small oscillatory or vibratory motion. It is characterized by the repeated, small relative motions between surfaces, which can lead to the removal of material, the formation of wear debris, and eventual damage at the contact points.
Hydrogen embrittlement is a phenomenon in which metals, particularly high-strength steels and some alloys, become fragile and susceptible to fracture when exposed to hydrogen. This occurs as hydrogen atoms diffuse into the metal and accumulate at certain sites within the material, leading to a reduction in ductility and toughness. ### Mechanisms of Hydrogen Embrittlement: 1. **Hydrogen Absorption**: Hydrogen can be introduced into metals through various processes, including electroplating, welding, and corrosion.
Low-cycle fatigue (LCF) is a type of fatigue that occurs in materials subjected to repeated or cyclic loading, leading to plastic deformations at an upper range of strain levels. It is typically characterized by a relatively low number of loading cycles (often less than 10,000 cycles) compared to high-cycle fatigue, which occurs at much lower stress levels and involves a much higher number of cycles, often exceeding one million.
Lumped Damage Mechanics (LDM) is a theoretical framework used primarily in the field of materials science and engineering to model the behavior of materials under loading conditions, particularly in relation to damage accumulation and failure. The fundamental concept of LDM is to simplify the treatment of damage in materials by considering it as a "lumped" parameter rather than a distribution throughout the material.
A Lüders band is a specific type of deformation band that forms in certain metallic materials, particularly ductile metals, when they are subjected to plastic deformation under tensile stress. Named after the German physicist Emil Lüders, these bands represent localized regions of strain that propagate through the material during the yielding process. When a material experiences strain hardening, it can initially deform uniformly, but as it reaches its yield strength, localized deformation may occur.
Nabarro–Herring creep, also known as Nabarro–Herring diffusion creep, is a mechanism of creep deformation that occurs in materials, particularly in polycrystalline metals and ceramics, at elevated temperatures and under constant load. This creep mechanism is named after two scientists, Sir Harold Nabarro and Sir Charles Herring, who independently described the phenomenon.
The National Centre for the Evaluation of Photoprotection (NCEPP) is likely to be an organization or center dedicated to research, evaluation, and promotion of photoprotection, which involves methods and products aimed at protecting the skin from the harmful effects of ultraviolet (UV) radiation. This may include the assessment of sunscreen efficacy, skin cancer prevention strategies, and public awareness initiatives regarding skin health and sun safety.
Neurolysis is a medical procedure that involves the destruction of nerve tissue. It is typically performed to relieve pain by disrupting the transmission of pain signals along a nerve. This procedure can be particularly useful for patients with chronic pain conditions that have not responded to other treatments. There are different methods of performing neurolysis, including: 1. **Chemical Neurolysis**: This technique utilizes chemical agents, such as phenol or alcohol, to denature the nerve tissue.
Ozone cracking, also known as ozone stress cracking or ozone-induced cracking, is a type of deterioration that affects certain materials, particularly elastic polymers like rubber. It occurs when rubber materials are exposed to ozone gas, typically in the atmosphere, especially at higher altitudes or in industrial environments where ozone levels may be elevated. Ozone molecules can penetrate the surface of the rubber material and react with the polymer chains, leading to the formation of cracks.
Photo-oxidation of polymers refers to the chemical reactions that occur in polymers due to exposure to light (particularly ultraviolet (UV) light) and oxygen. This process can lead to the degradation of polymer materials, affecting their physical and chemical properties. ### Key Points about Photo-Oxidation of Polymers: 1. **Mechanism**: - Photons provide energy that can excite electrons in polymer chains, leading to the formation of free radicals.
Pitting corrosion is a localized form of corrosion that leads to the creation of small, deep pits or cavities on the surface of a material, typically metals. This type of corrosion is particularly dangerous because it can cause significant material loss while often remaining visually undetectable until substantial damage has occurred. Key characteristics of pitting corrosion include: 1. **Localized Nature**: Unlike general corrosion, which affects the entire surface uniformly, pitting corrosion is localized, leading to small areas of intense damage.
Polymer degradation refers to the deterioration of the physical and chemical properties of a polymer as a result of exposure to various environmental factors or internal stresses. This process can lead to the breakdown of the polymer's structure, which can impact its performance, durability, and functionality.
Red rot is a term that can refer to a couple of distinct issues depending on the context, but it is most commonly associated with two main areas: 1. **In Plant Pathology:** Red rot is a disease that affects plants, particularly sugarcane and other grasses. It is caused by the fungus **Colletotrichum falcatum** and is characterized by the decay of plant tissues and a reddish discoloration of the affected areas.
The T-criterion, also known as the T-test, is a statistical method used to determine if there are significant differences between the means of two groups or a single group's mean compared to a known value. It is commonly employed in hypothesis testing to assess whether the observed data deviates significantly from the null hypothesis, which typically states that there is no effect or no difference.
Thermal degradation of polymers refers to the breakdown of polymer chains when exposed to high temperatures, leading to a loss of mechanical, physical, and chemical properties. This process can result in the production of smaller molecular fragments, gases, or other byproducts. Key points about thermal degradation include: 1. **Mechanism**: Thermal degradation typically occurs through processes such as chain scission (breaking of polymer chains), cross-linking (bonds forming between chains), or the release of volatile compounds.
Water droplet erosion refers to the process in which the impact of falling raindrops or flowing water on a surface causes material loss or damage. This phenomenon is primarily observed in areas where water is a significant factor in erosion, such as agricultural fields, construction sites, and natural landscapes. ### Mechanism of Water Droplet Erosion 1. **Impact Energy**: When a water droplet falls onto a surface, it carries kinetic energy.
"Wear" can refer to several contexts, depending on how it's used. Here are the primary meanings: 1. **Clothing and Accessories**: Most commonly, "wear" refers to garments or clothing items. It encompasses various styles and types of apparel, including casual wear, formal wear, and sportswear.
Weather testing of polymers refers to the process of evaluating the durability and performance of polymer materials when exposed to outdoor environmental conditions over time. This testing is essential for understanding how polymers behave under various weather-related stresses, such as UV radiation, temperature fluctuations, humidity, rain, and ozone exposure.
Articles by others on the same topic
There are currently no matching articles.