Zibo Special Chemicals Production Co., Ltd.

　　Anti-wear(AW)agents are crucial additives in engine oil,designed to protect critical metal components,such as the camshaft and valve train,under boundary and mixed lubrication conditions.These conditions occur during cold starts or high-load/low-speed operations when the hydrodynamic oil film is too thin to completely separate the surfaces.　　The primary function of an AW agent is to form a sacrificial protective layer on the metal surfaces.When localized heat and pressure from metal-to-metal contact are high,the additive chemically reacts with the metal.This reaction creates a durable,yet softer,film known as a tribofilm.　　The most widely used AW additive is Zinc Dialkyldithiophosphate(ZDDP),an organo-metallic compound containing zinc and phosphorus.Upon activation by heat and stress,ZDDP decomposes to form a glassy iron and zinc polyphosphate film.This film prevents direct contact,minimizing abrasive wear,scuffing,and seizing,and also acts as a powerful antioxidant to prolong oil life.　　Other anti-wear and friction-reducing compounds include Molybdenum compounds(like Molybdenum Dithiocarbamate),which form a low-friction solid film,and various ashless phosphorus-based compounds.Careful formulation ensures optimal wear protection while balancing modern engine oil requirements,such as compatibility with catalytic converters.

　　Decarburization refers to the loss of carbon from the surface layer of an alloy,typically steel,when it is heated to high temperatures(generally above 700℃)in an atmosphere containing oxygen or hydrogen.This phenomenon is categorized based on its extent and cause.　　1.Extent-Based Decarburization　　In metallurgical testing,decarburization is classified by the degree of carbon loss in the surface layer:　　Complete Decarburization(Type 1):This occurs when the carbon is completely removed,resulting in a measurable layer of pure ferrite(carbon-free iron)at the surface.　　Partial Decarburization(Type 2&3):This describes the transition layer where the carbon content gradually increases from the surface to the core’s original concentration.The loss is greater than 50%(Type 2)or less than 50%(Type 3)without a completely carbon-free layer.　　2.Intent-Based Decarburization　　From a process standpoint,decarburization is classified by whether it is an intended or unintended outcome:　　Incidental/Undesirable Decarburization:This is the most common and problematic type,occurring unintentionally during high-temperature manufacturing processes like forging,hot rolling,or heat treatment.It severely reduces the surface hardness,wear resistance,and fatigue strength of critical components like fasteners and gears.　　Intentional Decarburization:This is a controlled process used to achieve specific material properties.A prime example is the production of electrical steel(silicon steel),where low carbon content is required to minimize magnetic core losses,thus enhancing electrical efficiency.　　Preventing incidental decarburization usually involves using controlled atmospheres(inert gases or vacuum)during heating.

　　Using a desulfurizer involves employing a specific chemical or physical process to remove sulfur compounds,typically hydrogen sulfide(H2S)or sulfur dioxide(SO2),from a gas or liquid stream.The exact method depends entirely on the application(e.g.,natural gas,refinery products,or power plant flue gas)and the desulfurization agent used.　　1.Wet Scrubbing　　For large-scale flue gas desulfurization(FGD),wet scrubbing is common.The flue gas passes into a tower where it is contacted with a fine spray or slurry of an alkaline sorbent,most often limestone or lime(CaCO3 or Ca(OH)2).The sorbent reacts chemically with the SO2 to form a solid byproduct like calcium sulfite/sulfate(gypsum),which is then collected and removed.　　2.Amine/Chemical Absorption　　In natural gas and refinery processes(gas sweetening),a liquid desulfurizer like a tertiary amine(e.g.,MDEA)is circulated through an absorption column.The gas stream flows up,countercurrent to the amine solution,which selectively absorbs the H2S and CO2.The resulting"rich"amine is then sent to a separate regeneration column,where heat is applied to release the acid gases,allowing the"lean"amine to be recycled.　　3.Dry/Solid Adsorption　　For smaller scale or fine purification,dry desulfurizers like iron oxide(Fe2O3)pellets or activated carbon are used.The gas stream simply passes through a packed bed of this solid material.The sulfur compounds are chemically or physically adsorbed onto the surface of the media.Once saturated,the solid desulfurizer must be either replaced or regenerated,often through steam stripping or an oxidation step.　　These processes are critical for meeting environmental regulations and protecting downstream equipment from corrosion.

　　Anti-wear(AW)agents are essential chemical additives in lubricants,designed to protect contacting metal surfaces under boundary and mixed lubrication conditions.These regimes occur when the lubricant film is too thin to completely separate the moving parts,leading to metal-to-metal contact and potential damage.　　The primary principle of AW agents is to form a sacrificial protective film on the metal surface.When the localized heat and pressure from contact(known as"tribological stress")become high,the AW additives are chemically activated.They react with the metal to create a durable,yet softer,film—a tribofilm.　　A common example is Zinc Dialkyldithiophosphate(ZDDP),which reacts with the metal surface to form a glass-like polyphosphate film.This thin,protective layer(typically 50-150 nm thick)acts as a physical barrier.Instead of the hard metal surfaces wearing each other down,the softer tribofilm absorbs the shear stress,minimizing abrasive and adhesive wear.　　By providing this sacrificial coating,AW agents reduce friction,prevent component seizure,and significantly extend the lifespan of engines,gears,and hydraulic systems.