FR2862511A1 - Operating interface e.g. grill plate, coating for use in e.g. kitchen, has layers of titanium nitride, and obtained by plasma nitriding thermo-chemical processing - Google Patents

Abstract

The coating having a thickness in the order of few microns to few tens of microns has layers of titanium nitride. The coating is obtained by plasma nitriding thermo-chemical processing in which chemical reaction takes place between a gaseous compound with temperature of order of 600 to 1000 degree Celsius and a material surface to be processed. An independent claim is also included for an apparatus for kitchen and restaurant comprising interfaces provided with coatings.

Description

2862511 1

  The present invention relates to the professional interfaces for collective kitchens and restaurants, used for cooking food, such as grilling plates, stovetops for ovens, pots, frying pans, pancake plates, waffle molds, etc. .

  It relates in particular to the coating of these interfaces.

  In the usual way in this field, chrome plating treatments are used, in particular for professional cooking plates, which have notable drawbacks: chromium plating has no real anti-corrosion property, its range of use is reduced (from 0 to 350400 C) and its poor thermal shock resistance. In addition, the electrolytic copper first layer being very flexible, the slightest shock causes peeling of the second layer of electrolytic chromium. Finally, the use of electrolyte baths makes this treatment very heavy for the environment; and overheating (from 350 C depending on the application) of this treatment causes the migration of chromium ions to food or in gaseous form.

  The object of the invention is to provide a new type of coating for professional interfaces used for cooking food, which does not have these disadvantages, and which is safe for the consumer.

  To this end, the subject of the invention is a coating for professional interfaces used for cooking food, essentially consisting, according to the principles of obtaining used, of one or more layers of titanium nitride (TiN or Ti2N), the coating can generally be of the order of a few microns to tens of microns thick.

  Indeed, titanium nitride offers many advantages.

  It retains high mechanical characteristics up to at least 600 C. It is food, non-stick, and has a low thermal radiation. Its resistance to thermal shock and abrasion is excellent. Its coefficient of expansion is comparable to that of steel.

  Its amagnetism allows applications on stainless steel. In addition, it is anallergic, bacteriostatic and biocompatible, and its golden yellow color is very aesthetic.

  The coating according to the invention can be obtained by any type of process, current or future: for example, by a thermochemical treatment of ionic nitriding, known in itself, in which is established a chemical reaction between a compound 2862511 2 gaseous at temperatures of the order of 600 to 1000 C and the surface of the material to be treated.

  The coating according to the invention can also be obtained by a chemical vapor deposition technique CVD (Chemical Vapor Deposition), known in itself, which makes it possible to produce solid depositions, on various metallic supports, by chemical reaction of an active gas mixture (TiCl4 for example) thermally decomposed at temperatures of 800 to 1000 ° C and pressures of 10 to 100 mbar. This technique makes it possible to produce relatively homogeneous and uniform relatively thick layers of deposits even on complex shapes, as well as multilayer deposits that make it possible to optimize the performances according to the stresses of the coated element.

  The coating according to the invention can also be obtained by a physical vapor deposition technique (PVD) known per se, consisting in evaporating at low pressure a metal initially in the solid state, whose vapors are combined with a ionized gas to produce a hard compound in the form of a thin film, adherent, deposited around 400-550 C on the parts to be coated.

  The coating according to the invention may finally be obtained by a thermochemical process for the diffusion of nitrogen without plasma, carried out at low pressure, and known in itself, said process making it possible to obtain a deposition layer that is even harder than by the above-mentioned methods.

  All these surface treatments are known in themselves.

  However, it was not known to use these techniques to make a coating consisting essentially of titanium nitride for professional interfaces used for cooking food.

  A professional food-cooking interface with a titanium nitride coating according to the present invention will therefore have improved functional qualities, thanks to: - its anti-adhesion; - its food supply at all temperatures below 600 C; - its low thermal radiation; the possibility of using much higher cooking temperatures than with conventional coatings; 2862511 3 - strong enough to withstand thermal shock and abrasion in an incomparable way; - its high chemical stability.

  It will thus be safe for food, and will also have a very aesthetic golden color.

  The invention also relates to an apparatus of collective kitchens and restaurants having one or more interfaces provided with such a coating.

  Other advantages and features will appear more clearly on reading the following description of the invention, with reference to the accompanying drawings in which - Figure 1 is a schematic sectional view of a deposition layer resulting from a treatment usual by chrome plating; FIG. 2 is a diagrammatic sectional view of a coating layer according to the invention; FIG. 3 is a perspective view of an exemplary embodiment of the invention on a gas or electric apparatus with grilling plates; - Figure 4 is a schematic sectional view of the embodiment of Figure 3; FIG. 5 is a perspective view of an exemplary embodiment of the invention on a kettle; Figure 6 is a schematic sectional view of the embodiment of Figure 5; Figure 7 is a perspective view of an exemplary embodiment of the invention on a jumper; - Figure 8 is a schematic sectional view of the embodiment of Figure 7; - Figure 9 is a schematic sectional view of an embodiment of the invention on a waffle iron; - Figure 10 is a partial perspective view of an embodiment of the invention on a pancake.

  FIG. 1, which corresponds to the state of the prior art, shows that the deposition layer, which covers a professional chromium-plated steel 1 hotplate, consists of two layers: one of electrolytic copper 2 for adhesion, resulting from a first coppering operation; a second of electrolytic chromium 3, resulting from a second chromium plating operation.

  2 schematically represents a section of a coating 4 according to the invention, which covers a professional cooking plate 5 of steel 1.

  This coating 4 is of the order of a few microns to a few tens of microns thick; and it is according to the principles used, consisting essentially of one or more layers of titanium nitride.

  The following figures represent various collective kitchen appliances and restaurants coated with a coating layer 4 according to the invention, such as grilling plates (FIGS. 3 and 4), a cooking pot (FIGS. 5 and 6), a frying pan (FIGS. Figures 7 and 8), a waffle iron (Figure 9), a crepe maker (Figure 10).

  As is obvious, and as is apparent from the foregoing, the invention is not limited to the sole embodiment of this coating which has been described above, by way of example; it embraces, on the contrary, all variants of implementation and application respecting the same principle. Thus, in particular, one would not move away from the scope of the invention by applying it to interfaces for reheating, preservation or presentation of food.

Claims (2)

  1. Coating (4) for professional interfaces (1) for cooking food in communal kitchens and restaurants, such as grilling plates, oven hobs, cooking pots, frying pans, crepe plates , or waffle molds, characterized in that it consists essentially of one or more layers of titanium nitride, said coating (4) measuring from a few microns to a few tens of microns thick.   2. Apparatus for collective kitchens and restaurants having one or more interfaces provided with a coating according to claim 1.