Mora, one of the world’s largest knife manufacturers, has come a long way in its development. The beginning of its history dates back to 1891, when master craftsman Eric Frost founded his knife factory. This is how the largest knife company in Mora – Frost Knivfabrik – came into being. In 1912, two other craftsmen from the same town, Lok Anders Mattsson and Krang-Johan Eriksson, founded the company Eriksson & Mattssons Knivfabrik. Both KJ Eriksson and Frost Knivfabrik operated in parallel and were competitors throughout the twentieth century. In the early 2000s, the shares of Frost Knivfabrik were bought out by KJ Eriksson, and in 2005 the two companies merged completely. And there was a single company Morakniv, a large, powerful company with conveyor belt production of knives.

For almost a century, knife makers from the town of Mora produced classic Swedish knives made of carbon steel, with “Scandinavian” blade geometry and a wooden handle. These were mainly work and craft knives. The company Frost Knivfabrik also produced a large number of kitchen knives. And K.J.Eriksson produced a survival knife for Swedish Air Force pilots for several decades. The knife had a classic design, with a carbon steel blade and a birch wood handle. The blade was 10 cm long and 2.4 mm thick. The knife was equipped with a leather sheath with a short hanger, had a well-developed grip and a sling cutter on the edge. It was not intended for use in combat, but for survival of a pilot who had been in an accident. In 1995, the knife was removed from the Air Force and replaced by the legendary Fallkniven F1 survival knife.

Today, Morakniv produces a very large range of products. Among them are hiking, kitchen, work, garden, craft and fishing knives. In addition, axes, flame throwers, diamond and ceramic sharpening stones are produced. There is an opportunity for the buyer to purchase individual blades, and from a variety of steels: carbon, laminated or stainless steel. It is impossible to describe the full number of models of the company Mora, but we can highlight some.

Classic models are not a thing of the past, they are still produced and in demand. These knives have a wooden handle made of Scandinavian birch. The steel of the blades on these knives – classic carbon, with a hardness of about 58 HRC. In addition, laminated steel blades are also produced. The geometry of the blade on these models – drop point, Scandinavian descents brought to zero, the angle of the descents-underslopes about 20-23 degrees. Carbon steel on Mora knives is of good quality, not prone to creases, keeps sharpening well and is very easily corrected with any mousate from ceramic to diamond. However, it rusts very actively and requires maintenance. This problem can be solved by etching the blade in various substances, usually citric acid, vinegar, etc. are used for this purpose. They create a fairly stable film on the surface of the blade, protecting it from corrosion. An example of a classic knife of this company are models without a guard: Mora Classic No. 1, 2,3, as well as knives with a guard: Mora Classic 611 and Classic 612.

In 1976, KJ Eriksson began production of the 510 knife model with a plastic handle without a grip, and later the 511 with a grip. These knives were utilitarian tools designed for heavy work, construction and various industrial needs. The knives were very cheap and were produced in huge quantities. Initially they had a blade made of carbon steel only, but since the 90s they started to use stainless steel Sandvik 12C27. This is a good quality rolled steel, the main advantage of which is high strength, which it shows even in severe frost conditions. In Scandinavian zero descents on very hard wood, this steel can buckle, but there are ways to strengthen it: creating a micro-feed or a micro-lens. In the 2000s, the 510 was upgraded to the Craftline HighQ Allround, which had a rubber coating on the plastic handle and a scabbard with a plastic clip, which was very convenient to carry on the belt, even without a belt. And around 2015, this line of knives underwent changes, turning into the Mora Basic 511, Mora Basic 546 and similar models. Scabbards for these knives received an additional attachment, allowing to “double” the knives in a kind of pair, which can be useful primarily in construction and installation work. The handle of the working knife has been slightly changed, it has got an additional stop on the side of the tip, for more rigid fixation of the hand.

Mora’s most versatile knife model of the last 20 years has been the Companion model. It was a continuation of the popular Moga Clipper line of knives. This model is made with carbon and stainless steel. The knife has a very large number of colors, almost for every taste. It is medium-sized, lightweight, with comfortable and reliable plastic sheath. The knife is suitable for household work, use in construction, use in hiking.

Created in 1991, the Mora 2000 or as it was then called by K.J. Eriksson Mora 2000, almost 10 years later became the most popular outdoors knife in Russia. Fishermen, hunters and tourists bought this knife in mass. What was the reason for such popularity? Obviously, the factors of success of this model were: price, quality and availability for purchase – the knives were sold in almost every hunting store. The Mora 2000 knife is lightweight, with comfortable plunge sheath, grippy handle made of plastic and rubber, with a blade of interesting, original shape. The blade is made of Sandvik 12C27 stainless steel. In 2015, the 2000 model received a sequel in the form of the Mora Kansbol knife. The blade did not change in geometry, but instead of polishing, it acquired a stonevosh treatment. On the handle of the knife there is now a hole for the handle. Mora Kansbol, in addition to the usual sheath, is equipped with an additional multi-mount hanger. This hanger can be attached to Molli slings or backpack straps, which makes traveling in boats or on mountain slopes more convenient.

In 2012, Mora partnered with Light My Fire, a famous Swedish firestick manufacturer, to produce a new camping knife. It was a hybrid of Craftline HighQ Allround model, with a geometrically similar blade to the Mora 2000 knife, and a special notch in the tip of the knife, with FireSteel fire starter mounted there. The knife found its buyer and in time Mora decided to produce similar knives on its own. This model is now called Mora Companion Spark, it has a blade from Mora Companion, a plastic sheath with a hanging clip and a fire starter in the handle. The flame thrower is of good quality and allows you to reliably shoot out a sufficiently dense sheaf of sparks and ignite dry and prepared materials for burning: absorbent cotton, rubbish, small shavings, etc. The model turned out to be very successful, easy to use, lightweight and multifunctional.

Aluminum oxide is a binary compound of aluminum and oxygen. It is common in nature as the main constituent of alumina – a mixture of aluminum oxides and elements such as potassium, sodium, magnesium, etc. Alumina consists of up to 98% of α- and γ-modifications of aluminum oxide and is a white crystalline powder. There are several main varieties of aluminum oxide, but most commonly used in industry is α-oxide or corundum, which is a mineral in the form of large transparent crystals, trigonal singony.

Raw materials for aluminum oxide include bauxite (aluminum ore), alunite (alum stone), and nepheline (potassium and sodium aluminosilicate). For the production of high-strength corundum ceramics, aluminum oxide powder obtained by thermal decomposition of some aluminum salts of varying degrees of purity is used. Aluminum oxide obtained by decomposition of salts is a highly dispersed powder γ-Al2O3 (when calcined up to 1200°C) and has a high chemical activity.

Synthetic α-aluminum oxide (corundum) is used as: an intermediate in aluminum production, for refractory, chemical resistant and abrasive materials, in the production of components for lasers, for the manufacture of synthetic gemstones, etc. Electrocorundum is mainly used for sharpening, both on electric equipment and sharpeners, and for hand sharpening. Electrocorundum (alund, aloxite) is a crystalline aluminum oxide that is artificially produced by melting alumina. This is done in a continuous process in arc furnaces with subsequent crystallization of the substance. After baking, the synthesized corundum acquires a very high hardness, second only to diamond. The Mohs hardness index for electrocorundum is 9, which is practically marginal. The more aluminum oxide is contained in electrocorundum, the harder, stronger and lighter it becomes.

The most commonly used electrocorundum for sharpening is normal (alund). It is a type of electrocorundum containing 91% to 96% Al2O3 in its composition. It is smelted by reductive smelting from bauxite containing aluminum. This electrocorundum abrasive has high hardness and is suitable for grinding a wide variety of metals. The density of electrocorundum ranges from 3.8 g/cm³ to 3.9 g/cm³; the microhardness is approximately 18.6 GPa (Pascal) to 19.6 GPa (1900 kgf/mm² to 2000 kgf/mm²). The color of corundum depends on the impurity content. Unlike silicon carbide, aluminum oxide can have a minimum grain size of less than 1 µm, which allows for more efficient fine finishing of the cutting edge. Sharpening on aluminum oxide abrasives is well suited for most kitchen and hunting knives as well as carpentry tools.

Aluminum oxide is cleaner than silicon carbide works on steels below 58 HRC, leaving a less coarse risk on the approach. Due to the fact that the corundum grains do not split in the process of work, as in silicon carbide, and rolled, reducing in size and losing the sharpness of the edges, this abrasive works softer. At the same time, the difference in working speed between aluminum oxide and silicon carbide depends mainly on the hardness of the bond. Oxide stones are created on a vitreous ceramic bond while carbide stones are created on a porcelain bond, which is much softer. In addition, aluminum oxide stones work with oil, while silicon carbide stones work with an aqueous suspension, which has a greater abrasive effect. However, this does not apply to the stones of Naniwa Professional series, which due to the very high quality of abrasive powder and finely dispersed suspension, are able to work quickly and efficiently on any steel, including those above 58 HRC.

Examples of aluminum oxide sharpening stones include:

1. Boride T2 stones – The Boride T2 series of American Boride stones are made of ceramic vitreous bonded oxide. This results in high performance and a lower than average wear rate. Boride stone manufacturers recommend T2 as the best series for stainless steel. When sharpening with Boride T2 series stones, both oil-based and water-based coolants can be used. The stone is cleaned in water, with a stiff brush and a soap solution. Traces of oil-based coolant are effectively and quickly removed with cleaning oils such as TSPROF abrasive cleaning oil. Stones on thick glass or mirror are leveled with silicon carbide powder.

2. Boride PC (Polisher’s Choice) stones are a series of synthetic aluminum oxide stones of exceptionally high quality. The name of the stones literally translates to “Polisher’s Choice”. PC series stones are designed as finishing stones for the final finishing of metal to a mirror shine. Boride PC stones are used only with the application of coolant.

3. Naniwa Professional stones -an improved series of Japanese Naniwa stones. This series uses magnesia-bonded aluminum oxide. The stones do not require soaking, slow salting and high performance. The stones work gently, yet are fast enough due to their suspension. Naniwa Professional are suitable for virtually all steels.

The first historically known tools resembling knives are obsidian detachments – nuclei. That is, products made of volcanic glass were used by human ancestors several hundred thousand years ago. And having gone a long way in metallurgy, mankind returned to the use of ceramics at the end of the twentieth century. In 1985, the Japanese company Kyocera began production of ceramic knives based on zirconium dioxide. These knives were the result of the most advanced technology at that time. To date, such knives have become very widespread, at an extremely low price.

What a ceramic knife is made of

Ceramic knives are made from zirconium dioxide (ZrO2), which is obtained by special processing of the mineral zircon. Zircon (ZrSiO4) is a material belonging to the class of silicic acid salt minerals, which was discovered by the German chemist M.G. Klaproth in 1789. Zirconium (Latin: Zirconium; denoted by the symbol Zr) is a material of the periodic system, with atomic number 40. It is a lustrous metal, silvery gray in color. It is highly ductile and resistant to corrosion. Zirconium compounds are widely distributed in the lithosphere. In nature, its compounds are known exclusively with oxygen in the form of oxides and silicates. Despite the fact that zirconium is a diffuse element, there are about 40 minerals in which zirconium is present in the form of oxides or salts. The most common in nature are zircon (ZrSiO4), baddeleyite (ZrO2) and various complex minerals.

Zircon is the most common zirconium mineral. It occurs in all types of rocks, but mainly in granites and syenites. In Hinderson County, North Carolina, USA, zircon crystals several centimeters long have been found in pegmatites, and crystals weighing several kilograms have been found in Madagascar. Baddeleyite was discovered in 1892 in Brazil. The main deposit is in the Posus di Caldas region of Brazil. The largest zirconium deposits in terms of size are located in the United States, Australia, Brazil, and India.

Raw materials for zirconium production are zirconium concentrates with mass content of zirconium dioxide not less than 60-65%, obtained by enrichment of zirconium ores. The largest volumes of zirconium production are concentrated in Australia (40%) and South Africa (30%). The main methods of obtaining metallic zirconium from concentrate are chloride, fluoride and alkaline processes.

Zirconium has been used in industry since the 1930s, but its high cost limited its use. Metallic zirconium and its alloys are used in nuclear power. Zirconium has a very low thermal neutron capture cross section and a high melting point. Another application of zirconium is alloying. In metallurgy it is used as a ligature. It is used as a deoxidizer and deazotator. Zirconium alloying of steels (up to 0.8%) increases their mechanical properties and machinability. In industry, zirconium dioxide is used in the production of zirconium-based refractory materials, ceramics, enamels, glasses. It is used in dentistry for dental crowns. It is used as a superhard material. Zirconium dioxide conducts current when heated, which is sometimes used to produce heating elements that are stable in air at very high temperatures. Heated zirconia is able to conduct oxygen ions as a solid electrolyte. This property is used in industrial oxygen analyzers and fuel cells. What distinguishes zirconium ceramics from other materials is its tremendous heat resistance and hardness, which is usually not less than 80 HRC. In addition, zirconium oxide is completely unreactive to most acids, alkalis and other active substances.

Zirconium oxide is obtained from zircon by chemical processing with additives. The resulting powder is mixed with additives. There are sintering additives, which affect the sintering characteristics and quality of the finished ceramics, and auxiliaries, which aid in molding. Accordingly, zirconia blanks are manufactured by various techniques. In particular, it is possible to alloy zirconium dioxide with oxides having a cubic crystal lattice. The most commonly used oxides for this purpose are oxides of the elements – calcium and magnesium, as well as metals – iron, manganese, chromium. In addition, zirconium oxide is often alloyed with aluminum oxide. The alloying oxides can change the color of ceramics from white to black (black color can also be obtained by special treatment). For example, this is used in the coloring of fianites – artificial diamonds based on cubic zirconium oxide.

Zirconium dioxide has a high hardness, which is measured using the Mohs hardness scale of materials. The hardness of zirconium dioxide on the Mohs scale is about 8.5 units, while the hardness of steel on this scale, depending on the heat treatment, from 4 to 7 units, corundum about 9 units, diamond 10 units. Thus, the material from which ceramic knives are made, in terms of hardness is close to diamond. Zirconium ceramics is also used in jewelry, in the aviation industry and mechanical engineering, in dentistry. Zirconium dioxide has more than 80 times the wear resistance of steel.

HOW TO MAKE CERAMIC KNIVES

The technical process of creating zirconium blades is as follows: obtaining alloyed zirconium oxide powders, preparation of press compositions and pressing, firing at high temperature (1350C+, in some cases up to 1700C), hot isostatic pressing at high temperatures and pressure.

The process of making ceramic knives is quite labor-intensive. To produce a ceramic blade, zirconium dioxide powder is first pressed under a pressure of 300 tons per square centimeter, then heat treated at temperatures of 1600-2000 degrees Celsius in special ovens for a long time (from two to six days). At the same time, zirconium dioxide crystals are sintered and the process of forming blanks is underway. The longer the product is kept in the furnace, the stronger it becomes. Depending on the specifics of the technological process, black or white ceramics are obtained. Black ceramics are made by adding a special black dye and keeping the workpieces in the kiln for a longer period of time, as a result of which they become stronger. The quality of ceramic knives varies greatly, as it is highly dependent on the technological capacity of the manufacturer, and the adherence to a complex technological process.

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PLUSES AND MINUSES OF CERAMIC KNIVES

The properties of zirconia ceramics depend significantly on the technology used to produce them, ranging from the purity of the initial zirconia powder, alloying system, powder granulometry, sintering regimes, etc.

In terms of mechanical properties, zirconium ceramics are significantly inferior to the most common steels, in particular, in terms of bending strength by a factor of about two, and in terms of impact strength by several times. This severely limits the versatility of ceramic knives. Because of their brittleness, most manufacturers urge not to use these knives for meat with bones, frozen foods, work on hard surfaces (glass, ceramic), etc. However, it should be noted that ceramics have unique properties that are superior to steel in terms of corrosion resistance and inertness to food.

CHARGING A CERAMIC KNIFE

Due to the fragile nature of the cutting edge, a ceramic knife requires quite large sharpening angles. On average, it is recommended to sharpen it to a full angle between 30-40 degrees. Sharp angles of 20 degrees or less are contraindicated for such knives, as the fragility of the cutting edge at this angle of sharpening becomes very high. Sharpening of ceramic knives is complicated by the fact that in the process is not formed burr and control of the angle must be maintained with the help of special devices, primarily electronic angle meter. Thus the manual sharpening of ceramic knives, without the use of sharpeners, requires an extraordinary, virtuoso skill from the sharpener.

Not all abrasives can handle sharpening a ceramic knife. Budget stones made of silicon carbide and aluminum oxide can’t handle these knives. The quality of the grinding powder and bond plays a key role here. The American Boride CS-HD sharpening stones are very effective in sharpening ceramic knives. The grain size of the stone should not be very coarse, in particular the Boride CS-HD for sharpening ceramics should be started with a 320 grit stone, because a coarser abrasive will cause cracks on the cutting edge. Obviously, the reason for this result is the very high quality of the silicon carbide powder and ceramic porcelain bond used in this American manufacturer’s products.

Electroplated and organic bonded diamond stones also perform well when sharpening knives. A little less active in sharpening them are elboron stones, which do not remove the zirconium layer as quickly as diamonds. However, all these abrasives are suitable for this sharpening and produce a good cutting edge condition.