Boron carbide is one of the toughest engineering materials available; only diamond and cubic boron nitride are harder. With high bending strength, good corrosion resistance, and thermal conductivity favorable to applications like blast nozzles and pump seals. Machining boron carbide ceramic can be both expensive and time consuming due to its green or biscuit state not holding tight tolerances and shrinkage during sintering by about 20%.
Methods of manufacturing
Boron carbide (B4C) is one of the hardest materials known to man, boasting a hardness rating comparable to diamond and thermal stability. Used in applications where high wear resistance, strength at low weight, or thermal stability is crucial, such as ballistic ceramic armor tile protection for military personnel and vehicles against explosives, bullets, fragments or other projectiles – these characteristics make B4C an invaluable material.
how to make boron carbide ceramic? Traditionally, fully dense boron carbide parts have been manufactured using pressing techniques such as hot pressing or isostatic pressing as well as spark plasma sintering; these methods, however, come with several drawbacks including geometric complexity and size restrictions, equipment costs requirements as well as demanding post-sintering processes such as machining.
Herein lies the significance of the invention described herein: it concerns a method for producing a boron carbide ceramic that combines the advantages of green, biscuit, or partially sintered boron carbide with machined-fabricated boron carbide ceramic.
This method involves mixing mixed raw materials containing an amorphous B and C component with carbon nano fibers in an evenly dispersed state, and subjecting this mixture to simultaneous synthesis and sintering using the SPS method. This produces a sintered compact with high B4C content and superior mechanical properties; its composition can be tailored by altering its relative atomic percentages of boron and carbon for different performance characteristics.
Properties
Boron carbide B4C is a widely recognized ceramic material, distinguished by its low density, high Hugoniot elastic limit and super-high hardness properties. However, it suffers from poor damage tolerance and strength limiting its applications in many fields. In order to enhance these physical-mechanical properties, researchers have tried adding various sintering additives including oxides based on rare metals as well as pure silicon Si [3,6,7] but these can decrease sintering temperature/pressure thus producing denser denser material while negatively altering some unique properties that make B4C exceptional!
Recently, special materials have become a necessity in advanced electronic, space and computer technologies. These require high thermal stability as well as good abrasion resistance – something boron carbide ceramic can satisfy.
boron carbide ceramic is one of the hardest known substances and boasts exceptional strength, making it ideal for use as an abrasive and for cutting metal alloys such as titanium, aluminum and stainless steel. Furthermore, its strength has allowed it to be utilized for bulletproof vest manufacturing as it’s lighter than steel armor with greater impact resistance; more heat-resistant than aluminum as it can withstand temperatures over 1,800 degrees Celsius for extended periods without melting, making this material invaluable in military applications and highly resilient ceramic versions that withstand great amounts of stress than aluminum can ever manage alone! Lastly boron carbide ceramics offer extreme durability and stress resistance with great strength being among their ranks being.
Applications
Boron carbide is an extremely hard, durable material capable of withstanding high temperatures while possessing great wear resistance. Used in many industrial applications such as cutting, grinding, polishing and lapping applications; additionally it makes an excellent abrasive material used as armour on military equipment and vehicles such as helicopters that need protection from shell hits from below.
Due to its extreme hardness, boron carbide can be extremely challenging to drill through – this presents particular problems when building structures with ceramic components made from this material. Conventional machine drilling tools cannot penetrate it easily; instead specialized diamond drills may need to be employed instead for efficient drilling operations.
One approach for solving this problem involves using a tungsten carbide insert to drill holes through boron carbide ceramics. Unfortunately, this approach is both inefficient and time consuming; thus it would be preferable to find another means that could give access to the interior without needing to change out or remove and replace this component of the structure every time an insert needs replacing.
This invention describes a method for producing a sintered compact of boron carbide ceramic that contains carbon nano fiber (CNF) distributed uniformly across its surface. The ceramic is created directly by simultaneously synthesizing and sintering an amorphous B and C mixture; results show that one such compact with 15% by volume CNF exhibits excellent mechanical properties such as bending strength (710 MPa), Vickers hardness (364 GPa), and fracture toughness KIC (7.6 MPa*m1/2).
Benefits
Boron carbide is an extremely hard material that can be formed into various shapes. It boasts superior wear resistance and temperature resistance, and can even be used as an abrasive in water jet cutters to cut metals and other materials. Boron carbide has also found use as control rod material in nuclear power plants due to its ability to absorb thermal energy neutrons as well as being insoluble with nitric acid and unaffected by hot hydrogen fluoride environments.
Boron carbide ceramic can be produced using various processes, including pressureless sintering at high temperature (commonly referred to as spark plasma sintering; SPS). SPS powders are mixed with carbon nanofiber and sintered into dense shapes using pulsed direct current electric heating; this yields high three-point bending strength and abrasion resistance ceramics that produce durable three-point bendable pieces of ceramic boron carbide material.