Both the melting and boiling point increase with increase in pressure and decrease with decrease in pressure as it is directly proportional to the pressure.

However, the intermolecular forces in the liquid are not affected by this increase in atmospheric pressure. This is because of volume: Most solids have less volume than liquids, so melting would cause the solid to expand. Increasing pressure on the solid would make it harder for it to expand into a liquid.

Molecular composition, force of attraction and the presence of impurities can all affect the melting point of substances.

The more energy is needed, the higher the melting point. The melting temperature of a crystalline solid is thus an indicator for the stability of its lattice. At the melting point not only the aggregate state changes; quite a lot of other physical characteristics also change significantly.

One states a metal must have a melting point above 2200 °C, whilst the other states all metals with a melting point above 1850 °C are considered refractory metals.

Physical properties Of all metals in pure form, tungsten has the highest melting point (3,422 °C, 6,192 °F), lowest vapor pressure (at temperatures above 1,650 °C, 3,000 °F), and the highest tensile strength.

Top 10 Materials with the Highest Melting Point in the World

• Tantalum Hafnium Carbide Alloy (3990℃)
• Graphite (3652 ℃)
• Diamond (3550 ℃)
• Tungsten (3400 ℃)
• Titanium Boride (3225℃)
• Zirconium boride (3245℃)
• Rhenium (3180℃)
• Titanium Carbide (3100℃)

Among the metallic elements, only mercury has a lower melting point (−38.9 °C, or −38.02 °F) than cesium.

Tungsten

New record set for world’s most heat resistant material. Researchers have discovered that tantalum carbide and hafnium carbide materials can withstand scorching temperatures of nearly 4000 degrees Celsius.

Tungsten(Wolfram) is a great example since it has a melting point above 3000 °C, chromium, niobium molybdenum, rhenium, titanium and tantalum are all good examples that don’t melt below titanium’s minimal temp of 1668 °C…

Their findings showed hafnium carbide melted at just under 4000 degrees Celsius. Prior to the discovery of hafnium carbide’s high melting point, researchers from Brown University used computer modeling to predict a material made from hafnium, carbon and nitrogen would be the most heat resistant material.

The main groups of heat-resistant alloys are high chrome nickel austenitic alloys, also known as heat resistant stainless steel, nickel-based alloys, cobalt chrome nickel-based alloys, and molybdenum titanium alloys.

In terms of tensile strength, tungsten is the strongest out of any natural metal (142,000 psi). But in terms of impact strength, tungsten is weak — it’s a brittle metal that’s known to shatter on impact. Titanium, on the other hand, has a tensile strength of 63,000 psi.

High temperatures can compromise the the oxidation resistance of steel alloys, leading them to become rusted and weakening their structural integrity. As noted in an AK Steel data sheet on 304 stainless steel, the alloy reaches its melting point at the 2,550 °F – 2,650 °F (1399 °C – 1454 °C) range.

Coated fabrics are a common heat resistant fabric that are used in many industries. These fabrics are often used for protection purposes as they block the heat. Typical coatings include neoprene, silicone, ceramic, and refractory.

Heat Resistant Fabrics

• 3M Nextel Fabric. 3M Nextel Ceramic Insulation Fabrics are woven from continuous filament ceramic oxide fibers and represent a major advancement in refractory fiber technology.
• Zetex Fiberglass Fabric.
• Z-Flex Aluminized Fabric.

This study shows that, at low temperatures (<300 °C), the accelerated dehydration of cellulose was distinct in the pyrolysis of raw cotton. The activation energy of thermal decomposition for raw cotton (124 kJ/mol) determined under isothermal conditions at 200–300 °C was lower than that for scoured cotton (202 kJ/mol).

Mix 6 parts/lbs borax, 5 parts/lbs boric acid, 100 parts/12 gallons (45.4 L) water in a large container. Dip the fabric in until completely soaked. Repeat if needed. Allow to dry.

The main substance to be used in creating a home-made fire retardant solution is boron, which if saturated into fabric, cloth, paper and all sorts of other cellulose-based material (wood included) prevents them from burning. The idea is to get the respective materials saturated with boron salts.

Fire-retardant materials used in buildings

• Mineral wool.
• Gypsum boards.
• Asbestos cement.
• Perlite boards.
• Corriboard.
• Calcium silicate.
• Sodium silicate.
• Potassium silicate.