Modern science and high-tech industry are impossible without precision alloys — materials with unique physical characteristics achieved through strictly controlled chemical composition and manufacturing technology. These alloys are used in a wide range of applications: from magnetic transformer cores and thermally stable measuring-instrument components to turbine parts for aircraft engines and hermetic joints in spacecraft.
The history of precision alloys is a path of scientific discoveries, engineering experiments, and continuous improvement. Let us look at how this branch of metallurgy developed, which alloys became key, and how they are used today.
Invar was the first precision alloy, developed in the late 19th century by the French physicist Charles Édouard Guillaume. The scientist was seeking a more affordable alternative to expensive platinum–iridium alloys for length and mass standards. In the first half of the 20th century, the field of application of precision alloys expanded considerably — they began to be used in aviation, electrical engineering, and instrument making.
After World War II, rapid scientific and technical progress drove demand for materials with highly precise characteristics. Precision alloys began to be widely used in radio electronics thanks to their stable magnetic and electrical properties.
These alloys are characterized by high magnetic permeability and low coercivity, which makes them ideal for operation in alternating magnetic fields: transformers, chokes, electromagnets, and various sensors.
Permalloy is an iron–nickel alloy with high magnetic permeability and low coercivity, developed in 1913 by engineer Gustav Elmen at the Western Electric laboratories (later Bell Labs).
During the rapid growth of telephone communications and radio, engineers faced signal losses in transformers. Ordinary ferromagnets (for example, iron) had too high a coercivity, which caused energy losses during remagnetization. In the 1860s, signal transmission speed over telegraph cables was only 10–12 words per minute. In 1902, Carl Emil Krarup proposed wrapping the cable with iron wire to compensate for losses, increasing inductance and turning it into a loaded line to reduce distortion. However, iron did not have high enough permeability to compensate a transatlantic-length cable. After a long search, permalloy was discovered: wrapping with permalloy tape made it possible to increase signal transmission speed over a telegraph cable by a factor of four.
The appearance of permalloy in 1913 resulted from research by American engineer Gustav Elmen, who sought a material with the best magnetic characteristics. Classical permalloy contained 79% nickel and 21% iron, and this composition is still considered one of the optimal ones.
Stages in the development of permalloy:
Today permalloy is widely used in modern pulse transformers, microcircuits, medical equipment, magnetic shields, and even in precision mechanical instruments.
Another alloy, developed in 1929 by Gustav Elmen at Bell Labs in the United States. The creation of permendur was driven by the need for materials with improved magnetic properties for the growing number of electrical and electronic devices. Researchers experimented with various metal combinations to improve magnetic characteristics. As a result, permendur was developed — an alloy of iron, cobalt, and vanadium.
Key advantages of permendur:
Since its creation, permendur has found wide use in various industries, including electrical engineering, electronics, and instrument making. Its unique magnetic properties made it an indispensable material for efficient and reliable devices.
Permendur is used in the manufacture of:
At PZPS you can purchase cold-rolled strip of permalloy grades 50N, 50NP, 79NM and permendur 49K2FA-VI — an alloy with high uniformity of magnetic properties and stable characteristics after heat treatment.
In a number of engineering tasks it is required that a material does not change its geometric dimensions when temperature fluctuates over a wide range. This is important in instrument making, optical engineering, aerospace, nuclear power, and electronics.
The discovery of invar (from the English invariable, i.e. “unchanging”) belongs to the Swiss physicist Charles Édouard Guillaume, who in 1908 found that at about 36% nickel in an iron alloy the thermal expansion coefficient drops sharply. This discovery resulted from long experiments and research in alloys and led to a revolution in precision engineering and measuring technology. For the discovery of invar, Charles Guillaume received the Nobel Prize in 1920.
Alloy features:
Invar practically does not change its dimensions when temperature varies over a wide range. This property made invar a valuable material for parts and equipment where dimensional stability is critical.
Applications of invar:
Grade 36N, produced at PZPS, matches the classical characteristics of invar and is successfully used in the most demanding applications.
Kovar is an iron–nickel–cobalt alloy created for joining metal and borosilicate glass. Its coefficient of linear thermal expansion is matched to the CTE of glass, which prevents failure of hermetic housings under thermal cycling.
The exact date of kovar’s creation is unknown, but its discovery occurred at roughly the same time as invar’s — in the early 20th century. This alloy was developed for use under temperature differentials.
Kovar is an alloy with a unique CTE close to the expansion coefficient of borosilicate glass: 4.9–5.1×10⁻⁶ 1/°C. Areas of application:
At PZPS you can buy cold-rolled kovar strip of grade 29NK, which provides hermetic and reliable joints of metals with ceramics or glass.
Such materials are used in heating elements and resistors.
Fechral is an alloy of iron, chromium, and aluminum. It has high heat-resistance properties and is widely used in industry for making heating elements.
Exact data on when and where fechral was created are lacking, but its development belongs to the period of active progress in metallurgy and electrical engineering in the late 19th and early 20th centuries. At that time scientists and engineers worldwide sought new materials that could withstand high temperatures and resist corrosion.
Fechral was developed as a material capable of withstanding extreme operating conditions such as high temperatures and oxidizing environments. Thanks to its unique properties, it quickly found use in various industries, including electric heaters, furnaces, and other equipment requiring elevated material heat resistance.
Properties of fechral:
Over time fechral became one of the most popular materials for heating elements thanks to its reliability, durability, and relatively low cost. It continues to be used in various industries to this day.
PZPS produces cold-rolled fechral strip of grades Kh15Yu5, Kh23Yu5, and Kh23Yu5T.
Nichrome (from the words “nickel” and “chromium”) was developed in 1905 by the English physicist and metallurgist Albert Marsh and became the first material mass-used in household electric heaters.
Composition:
Advantages:
Initially nichrome was used in industry for heating elements of electric furnaces, toasters, hair dryers, and other equipment. Over time nichrome also found use in aviation, space technology, and the chemical industry. It is used for parts that must withstand high temperatures.
Today nichrome remains one of the most popular materials for heating elements and other parts requiring high heat and corrosion resistance. At PZPS you can buy cold-rolled nichrome strip of grades Kh15N60-N — for household heaters, Kh20N80-N — for high-temperature applications and laboratory equipment.
Precision alloys have become an integral part of modern industry and science. Their creation is the result of many years of research, engineering ingenuity, and continuous development of metallurgical technologies. Permalloy, invar, kovar, permendur, fechral, and nichrome combine precise calculations, complex phase diagrams, and atomic-level control. Without them, satellites, electronic instruments, medical sensors, and high-temperature units would be impossible.
PZPS makes a substantial contribution to the development and production of precision materials. Our plant collaborates with research institutes and supplies industry with quality materials.
At PZPS you can order cold-rolled strip of all the alloys described (permalloys, invar, kovar, permendur, fechral, nichrome).
PZPS is your reliable partner in the production of high-precision materials. We ensure stable quality, technical support, and an individual approach to each customer.
