JPS6320449A - Titanium plated steel sheet having excellent heat resistance - Google Patents

Abstract

PURPOSE:To provide the titled Ti plated steel sheet which prohibits the inter- diffusion of Ti of a plating layer and the iron of a base material to prevent the formation of an Fe-Ti alloy layer and is highly resistant to heat by having an AlN layer having a prescribed thickness range on the surface of the steel sheet and subjecting the surface thereof to vacuum deposition plating of Ti. CONSTITUTION:The inside of a vacuum chamber 4 is evacuated to about 10<-4>-10<-5>Torr and nitrogen is ionized by the operation of an ion beam generator 6. The ions are made to entrain the Ti vapor evaporated by an electron gun 8, etc., in a Ti evaporating vessel 7 and to arrive simultaneously at the surface of the steel strip 1 to from the TiN film. The thickness of said film is adjusted to 100nm-1mum by controlling the line speed. The steel strip 1 after the formation of said film is then fed to a Ti vacuum deposition region 10, where Ti vapor evaporated by the electron gun 8' in the Ti evaporating vessel 7' is deposited by evaporation on the TiN film. The steel strip 1 with which the vapor deposition is completed is coiled by a coiling roll of a coil taking out chamber 5 and is taken out.

Description

[Detailed description of the invention] Industrial application fields> The present invention relates to a titanium-plated steel sheet with excellent heat resistance.

Conventional technologies and their problems> Despite the excellent properties of titanium plating, conventional titanium-plated steel sheets have not been put into practical use because they are difficult to manufacture by hot-dip plating or electroplating. Manufacturing methods are being studied, and the opportunity for practical application is ripe. However, when titanium-plated steel sheets manufactured by such vapor deposition are used at high temperatures, a thick layer of extremely brittle F@-Ti alloy is immediately formed, resulting in poor performance such as workability, corrosion resistance, and surface appearance. is significantly inhibited.

In view of this problem, the present invention aims to reduce the amount of titanium in the plating layer by forming a layer of titanium nitride between the steel sheet and the plating layer when producing titanium-plated steel sheets by vacuum evaporation. This prevents the formation of a Fe--Ti alloy layer by inhibiting the diffusion of iron and base metal iron.

<Structure of the Invention> That is, according to the present invention, titanium plating with excellent heat resistance is obtained by having a titanium nitride layer with a thickness of 1100 nm to 1 μm on the surface of a steel plate, and applying vacuum evaporation plating of titanium thereon. Steel plate is provided.

In the present invention, a TiN layer of at least about 100 nm is required to prevent diffusion of Fe and Ti. However, if the thickness exceeds 1μ, the workability of the plated steel sheet deteriorates, so from the viewpoint of use of the steel sheet, 100n layers or 1 layer is appropriate.

When manufacturing titanium-plated steel sheets using the vacuum evaporation plating method,
Steel plate tome! ! Forming a titanium nitride layer during the process can be performed relatively easily using an ion beam generator (ion source device).

<Specific Disclosure of the Invention> Next, the present invention will be specifically explained by way of examples with reference to the drawings, but this is not intended to limit the present invention in the same way.

FIG. 1 is a sectional view showing the concept of an apparatus for manufacturing titanium-plated steel sheets of the present invention. The device consists of three vacuum chambers that can be evacuated. That is, a coil loading chamber 3, a vapor deposition chamber 4, and a coil unloading chamber 5. The coil I is loaded into this charging chamber prior to operation.

The deposition chamber 4 includes a titanium nitride layer forming region 9 in which a nitrogen ion beam generator 6, a titanium evaporation tank 7, and an electron gun 8 are provided.
, a titanium evaporation area 10 provided with a titanium evaporation tank 7° and an electron gun 8'.

Next, the coils may be loaded in the three chambers under atmospheric pressure (this is done at the beginning of the operation), but during continuous operation, the coils are loaded by tightening the steel strip l with the elastomer valve 2. It is efficient to return only the entrance chamber 3 to atmospheric pressure, weld the steel strip of the next coil to the copper strip of the previous coil, depressurize the coil charging chamber, and then open the valve. When taking out the coil, the valve 2' is similarly tightened, the coil is taken out, and only the chamber 5 is returned to atmospheric pressure.

For continuous operation on a larger scale, the patent application
2574 may be used.

The nitrogen gas ion beam generator is described in detail in, for example, "Ion Source Engineering" written by Junzo Ishikawa and published by Ionics. .

The pressure in the vacuum chamber is reduced to about 10-' to 10-' Torr, nitrogen is ionized in the above-mentioned device, and at the same time titanium vapor evaporated by an electron gun 8 or the like in the titanium evaporation tank 7 is entrained and deposited on the surface of the steel plate. A titanium nitride film is formed there. The coating thickness can be adjusted by adjusting the line speed. The copper strip that has been coated with titanium nitride then proceeds to a titanium vacuum deposition region 10.
Here, titanium vapor heated and evaporated in a crucible is deposited on the titanium nitride coating. Although the operation of ion beam generators is known to those skilled in the art, the ion acceleration voltage 40
It is appropriate to carry out the test at approximately kV and current IA.

The steel plate that has been vapor-deposited in this way is rolled onto a take-up roll lO
is wound up. It is extracted by the operation described above.

Next, a titanium nitride layer with a thickness of 300 nm was applied, and then titanium was deposited to a thickness of 10 JL on specimens and titanium evaporated plated (10 gm) without a titanium nitride coating.
Figures 2 and 3 show the results of elemental analysis by EPMA of a cross section of a steel plate specimen coated with a titanium nitride layer (Figure 3) held at 800°C for 3 hours. It can be seen that, on the other hand, in the sample having a titanium nitride layer (FIG. 2), the plating layer maintains its titanium state. Table 1 shows the results of measuring the thickness of the alloy layer when aluminum was vapor-deposited while changing the thickness of the titanium nitride layer and similarly held at 800° C. for 3 hours.

Table 1 <Effects of the Invention> As described above, according to the present invention, by providing a layer of titanium nitride between the plating layer and the steel sheet of a titanium-plated steel sheet manufactured by a vacuum evaporation method, the plating layer and the matrix Since mutual diffusion of materials can be prevented, it is possible to use the steel sheet while maintaining the properties and surface appearance of the plating layer itself, even at relatively high temperatures. Moreover, the apparatus for forming this nitride layer can be achieved by relatively simple modification of a vacuum evaporation plating apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of the apparatus used to produce galvanized steel sheets according to the present invention. FIG. 2 is a graph showing the results of elemental analysis by EPMA of a cross section of an unexploited titanium-plated steel plate held at 800° C. for 3 hours. Figure 3 shows the E of the cross section of a conventional titanium-plated steel sheet held at 800°C for 3 hours.
It is a graph showing the results of elemental analysis by PMA.

Claims (1)

[Claims] 1. A titanium-plated steel sheet with excellent heat resistance, which has an aluminum nitride layer with a thickness of 100 nm to 1 μm on the surface of the steel sheet, and vacuum evaporation plating of titanium is applied thereon.