refractory metals are a class of metals that are extraordinarily resistant to heat and wear.the expression is mostly used in the context of materials science, metallurgy and engineering.the definition of which elements belong to this group differs. the most common definition includes five elements: two of the fifth period niobium and molybdenum and three of the sixth period tantalum .
copper alloys are metal alloys that have copper as their principal component. they have high resistance against corrosion.the best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. both of these are imprecise terms, having both been commonly referred to as lattens in the past. today the term copper alloy tends to be substituted, especially .
yttrium barium copper oxide ybco is a family of crystalline chemical compounds, famous for displaying high-temperature superconductivity.it includes the first material ever discovered to become superconducting above the boiling point of liquid nitrogen 77 k at about 92 k.many ybco compounds have the general formula y ba 2 cu 3 o 7−x also known as y123 , although materials with other y .
platinum is a chemical element with the symbol pt and atomic number 78. it is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. its name is derived from the spanish term platino, meaning 'little silver'. platinum is a member of the platinum group of elements and group 10 of the periodic table of elements.
tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. it is part of the refractory metals group, which are widely used as minor components in alloys. the chemical inertness of tantalum makes it a valuable substance for laboratory equipment and a substitute for platinum.
zinc is a chemical element with the symbol zn and atomic number 30. zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. it is the first element in group 12 of the periodic table.in some respects zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state 2 , and the zn 2 and mg 2 ions are of .
the data values of standard electrode potentials are given in the table below, in volts relative to the standard hydrogen electrode, and are for the following conditions: . a temperature of 298.15 k 25.00 c; 77.00 f . an effective concentration of 1 mol/l for each aqueous species or a species in a mercury amalgam an alloy of mercury with another metal .
both samples contained metals that included al, fe, li, v, cr, mn, ni, cu, zn, as, cd, sn, and pb. in addition, it had been confirmed that the concentration was higher in the first sample that was by the shipyard then the sample taking 500m away and was due to paint fragments applied to the steel ship hulls.
cupronickel or copper-nickel cuni is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. the copper content typically varies from 60 to 90 percent. monel metal is a nickel-copper alloy that contains a minimum of 52 percent nickel. despite its high copper content, cupronickel is silver in colour.
aluminium alloys with a wide range of properties are used in engineering structures. alloy systems are classified by a number system or by names indicating their main alloying constituents din and iso .selecting the right alloy for a given application entails considerations of its tensile strength, density, ductility, formability, workability, weldability, and corrosion resistance, to name a few.
platinum is a chemical element with the symbol pt and atomic number 78. it is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal.its name is derived from the spanish term platino, meaning 'little silver'.. platinum is a member of the platinum group of elements and group 10 of the periodic table of elements.it has six naturally occurring isotopes.
lead / ˈ l ɛ d / is a chemical element with the symbol pb from the latin plumbum and atomic number 82. it is a heavy metal that is denser than most common materials. lead is soft and malleable, and also has a relatively low melting point. when freshly cut, lead is silvery with a hint of blue; it tarnishes to a dull gray color when exposed .
these uptake rates also seem to be influenced by ph where at a ph of 7.1, zn was the most highly absorbed metal, at a ph of 4, pb was the most highly absorbed metal and at a ph of 5, cu was the most highly absorbed metal. cunninghamella echinulata has been used to transform cortexolone to hydrocortisone.
solder alloys are metallic materials that are used to connect metal workpieces. this is achieved by melting the alloy and then cooling it down. the choice of specific alloy depends on its melting point, chemical reactivity, mechanical properties, toxicity, and other properties.hence a wide range of solder alloys exist, and only major ones are listed below.
germanium is recovered as a by-product from sphalerite zinc ores where it is concentrated in amounts as great as 0.3%, especially from low-temperature sediment-hosted, massive zn–pb–cu –ba deposits and carbonate-hosted zn–pb deposits.
the flame test is relatively quick and simple to perform and can be carried out with the basic equipment found in most chemistry laboratories. however, the range of elements positively detectable under these conditions is small, as the test relies on the subjective experience of the experimenter rather than any objective measurements. the test .
naturally occurring nickel 28 ni is composed of five stable isotopes; 58 ni, 60 ni, 61 ni, 62 ni and 64 ni with 58 ni being the most abundant 68.077% natural abundance . 26 radioisotopes have been characterised with the most stable being 59 ni with a half-life of 76,000 years, 63 ni with a half-life of 100.1 years, and 56 ni with a half-life of 6.077 days.